WL#3527: Extend IGNORE INDEX so places where index is ignored

         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

1 files changed, 80 insertions, 78 deletions

diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 704c505ded9..b067443ba8c 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -150,6 +150,7 @@ static bool is_native_function(THD *thd, const LEX_STRING *name)
   struct st_lex *lex;
   sp_head *sphead;
   struct p_elem_val *p_elem_value;
+  enum index_hint_type index_hint;
 }
 
 %{
@@ -820,7 +821,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	btree_or_rtree
 
 %type <string_list>
-	key_usage_list using_list
+	using_list
 
 %type <key_part>
 	key_part
@@ -890,7 +891,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	opt_column_list grant_privileges grant_ident grant_list grant_option
 	object_privilege object_privilege_list user_list rename_list
 	clear_privileges flush_options flush_option
-	equal optional_braces opt_key_definition key_usage_list2
+	equal optional_braces
 	opt_mi_check_type opt_to mi_check_types normal_join
 	db_to_db table_to_table_list table_to_table opt_table_list opt_as
 	handler_rkey_function handler_read_or_scan
@@ -924,6 +925,8 @@ END_OF_INPUT
 %type <spblock> sp_decls sp_decl
 %type <lex> sp_cursor_stmt
 %type <spname> sp_name
+%type <index_hint> index_hint_type
+%type <num> index_hint_clause
 
 %type <NONE>
 	'-' '+' '*' '/' '%' '(' ')'
@@ -5523,12 +5526,8 @@ keycache_list:
 assign_to_keycache:
         table_ident cache_keys_spec
         {
-          LEX *lex=Lex;
-          SELECT_LEX *sel= &lex->select_lex;
-          if (!sel->add_table_to_list(lex->thd, $1, NULL, 0,
-                                      TL_READ,
-                                      sel->get_use_index(),
-                                      (List<String> *)0))
+          if (!Select->add_table_to_list(YYTHD, $1, NULL, 0, TL_READ, 
+                                      Select->pop_index_hints()))
             YYABORT;
         }
         ;
@@ -5555,33 +5554,26 @@ preload_list:
 preload_keys:
 	table_ident cache_keys_spec opt_ignore_leaves
 	{
-	  LEX *lex=Lex;
-	  SELECT_LEX *sel= &lex->select_lex;
-	  if (!sel->add_table_to_list(lex->thd, $1, NULL, $3,
-                                      TL_READ,
-                                      sel->get_use_index(),
-                                      (List<String> *)0))
+	  if (!Select->add_table_to_list(YYTHD, $1, NULL, $3, TL_READ,
+                                      Select->pop_index_hints()))
             YYABORT;
 	}
 	;
 
 cache_keys_spec:
-        { Select->interval_list.empty(); }
-        cache_key_list_or_empty
-        {
-          LEX *lex=Lex;
-          SELECT_LEX *sel= &lex->select_lex;
-          sel->use_index= sel->interval_list;
+        { 
+          Lex->select_lex.alloc_index_hints(YYTHD);
+          Select->set_index_hint_type(INDEX_HINT_USE, 
+                                      global_system_variables.old_mode ? 
+                                        INDEX_HINT_MASK_JOIN : 
+                                        INDEX_HINT_MASK_ALL);
         }
+        cache_key_list_or_empty
         ;
 
 cache_key_list_or_empty:
-	/* empty */	{ Lex->select_lex.use_index_ptr= 0; }
-	| opt_key_or_index '(' key_usage_list2 ')'
-	  {
-            SELECT_LEX *sel= &Lex->select_lex;
-	    sel->use_index_ptr= &sel->use_index;
-	  }
+	/* empty */	{ }
+	| key_or_index '(' opt_key_usage_list ')'
 	;
 
 opt_ignore_leaves:
@@ -6949,20 +6941,16 @@ normal_join:
 table_factor:
 	{
 	  SELECT_LEX *sel= Select;
-	  sel->use_index_ptr=sel->ignore_index_ptr=0;
 	  sel->table_join_options= 0;
 	}
         table_ident opt_table_alias opt_key_definition
 	{
-	  LEX *lex= Lex;
-	  SELECT_LEX *sel= lex->current_select;
-	  if (!($$= sel->add_table_to_list(lex->thd, $2, $3,
-					   sel->get_table_join_options(),
-					   lex->lock_option,
-					   sel->get_use_index(),
-					   sel->get_ignore_index())))
+	  if (!($$= Select->add_table_to_list(YYTHD, $2, $3,
+					   Select->get_table_join_options(),
+					   Lex->lock_option,
+					   Select->pop_index_hints())))
 	    YYABORT;
-          sel->add_joined_table($$);
+          Select->add_joined_table($$);
 	}
 	| '{' ident table_ref LEFT OUTER JOIN_SYM table_ref
           ON
@@ -7031,8 +7019,7 @@ table_factor:
 	    lex->current_select= sel= unit->outer_select();
 	    if (!($$= sel->
                   add_table_to_list(lex->thd, new Table_ident(unit), $6, 0,
-				    TL_READ,(List<String> *)0,
-	                            (List<String> *)0)))
+				    TL_READ)))
 
 	      YYABORT;
             sel->add_joined_table($$);
@@ -7131,52 +7118,67 @@ opt_outer:
 	/* empty */	{}
 	| OUTER		{};
 
+index_hint_clause:
+       /* empty */             
+         { 
+            $$= global_system_variables.old_mode ? 
+                  INDEX_HINT_MASK_JOIN : INDEX_HINT_MASK_ALL; 
+         } 
+       | FOR_SYM JOIN_SYM      { $$= INDEX_HINT_MASK_JOIN;  }
+       | FOR_SYM ORDER_SYM BY  { $$= INDEX_HINT_MASK_ORDER; }
+       | FOR_SYM GROUP BY      { $$= INDEX_HINT_MASK_GROUP; }
+       ;
+
+index_hint_type:
+       FORCE_SYM  { $$= INDEX_HINT_FORCE; }
+       | IGNORE_SYM { $$= INDEX_HINT_IGNORE; } 
+       ;
+
+index_hint_definition:
+       index_hint_type key_or_index index_hint_clause
+       {
+         Select->set_index_hint_type($1, $3);
+       }
+       '(' key_usage_list ')';
+       | USE_SYM key_or_index index_hint_clause
+       {
+         Select->set_index_hint_type(INDEX_HINT_USE, $3);
+       }
+       '(' opt_key_usage_list ')';
+
+
+index_hints_list:
+       index_hint_definition         
+       | index_hints_list index_hint_definition
+       ;
+
+opt_index_hints_list:
+       /* empty */
+       | { Select->alloc_index_hints(YYTHD); } index_hints_list
+       ;
+
 opt_key_definition:
-	/* empty */	{}
-	| USE_SYM    key_usage_list
-          {
-	    SELECT_LEX *sel= Select;
-	    sel->use_index= *$2;
-	    sel->use_index_ptr= &sel->use_index;
-	  }
-	| FORCE_SYM key_usage_list
-          {
-	    SELECT_LEX *sel= Select;
-	    sel->use_index= *$2;
-	    sel->use_index_ptr= &sel->use_index;
-	    sel->table_join_options|= TL_OPTION_FORCE_INDEX;
-	  }
-	| IGNORE_SYM key_usage_list
-	  {
-	    SELECT_LEX *sel= Select;
-	    sel->ignore_index= *$2;
-	    sel->ignore_index_ptr= &sel->ignore_index;
-	  };
+       {  Select->clear_index_hints(); }
+       opt_index_hints_list
+       ;
 
-key_usage_list:
-	key_or_index { Select->interval_list.empty(); }
-        '(' key_list_or_empty ')'
-        { $$= &Select->interval_list; }
+opt_key_usage_list:
+	/* empty */ 		{ Select->add_index_hint(YYTHD, NULL, 0); }
+	| key_usage_list	{}
 	;
 
-key_list_or_empty:
-	/* empty */ 		{}
-	| key_usage_list2	{}
-	;
+key_usage_element:
+	ident           { Select->add_index_hint(YYTHD, $1.str, $1.length); }
+	| PRIMARY_SYM   
+          { 
+            Select->add_index_hint(YYTHD, (char *)"PRIMARY", 7); 
+          }
+        ;
 
-key_usage_list2:
-	key_usage_list2 ',' ident
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String((const char*) $3.str, $3.length,
-				    system_charset_info)); }
-	| ident
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String((const char*) $1.str, $1.length,
-				    system_charset_info)); }
-	| PRIMARY_SYM
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String("PRIMARY", 7,
-				    system_charset_info)); };
+key_usage_list:
+        key_usage_element
+	| key_usage_list ',' key_usage_element
+        ;
 
 using_list:
 	ident