sql_hints.yy

/*
   Copyright (c) 2015, 2023, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/*
  Optimizer hint parser grammar
*/

%{
#include "sql_class.h"
#include "parse_tree_hints.h"
#include "sql_lex_hints.h"
#include "sql_const.h"

#define NEW_PTN new (thd->mem_root)
%}

%pure-parser
%yacc

%parse-param { class THD *thd }
%parse-param { class Hint_scanner *scanner }
%parse-param { class PT_hint_list **ret }

%lex-param { class Hint_scanner *scanner }

%expect 0


/* Hint keyword tokens */

%token MAX_EXECUTION_TIME_HINT

%token BKA_HINT
%token BNL_HINT
%token DUPSWEEDOUT_HINT
%token FIRSTMATCH_HINT
%token INTOEXISTS_HINT
%token LOOSESCAN_HINT
%token MATERIALIZATION_HINT
%token NO_BKA_HINT
%token NO_BNL_HINT
%token NO_ICP_HINT
%token NO_MRR_HINT
%token NO_RANGE_OPTIMIZATION_HINT
%token NO_SEMIJOIN_HINT
%token MRR_HINT
%token QB_NAME_HINT
%token SEMIJOIN_HINT
%token SUBQUERY_HINT

/* Other tokens */

%token HINT_ARG_NUMBER
%token HINT_ARG_IDENT
%token HINT_ARG_QB_NAME

%token HINT_CLOSE
%token HINT_ERROR

/* Types */
%type <hint_type>
  key_level_hint_type_on
  key_level_hint_type_off
  table_level_hint_type_on
  table_level_hint_type_off

%type <hint>
  hint
  max_execution_time_hint
  index_level_hint
  table_level_hint
  qb_level_hint
  qb_name_hint

%type <hint_list> hint_list

%type <hint_string> hint_param_index

%type <hint_param_index_list> hint_param_index_list opt_hint_param_index_list

%type <hint_param_table>
  hint_param_table
  hint_param_table_ext
  hint_param_table_empty_qb

%type <hint_param_table_list>
  hint_param_table_list
  opt_hint_param_table_list
  hint_param_table_list_empty_qb
  opt_hint_param_table_list_empty_qb

%type <hint_string>
  HINT_ARG_IDENT
  HINT_ARG_NUMBER
  HINT_ARG_QB_NAME
  opt_qb_name

%type <ulong_num>
  semijoin_strategy semijoin_strategies
  subquery_strategy
%%


start:
          hint_list HINT_CLOSE
          { *ret= $1; }
        | hint_list error HINT_CLOSE
          { *ret= $1; }
        | error HINT_CLOSE
          { *ret= NULL; }
        ;

hint_list:
          hint
          {
            $$= NEW_PTN PT_hint_list(thd->mem_root);
            if ($$ == NULL || $$->push_back($1))
              YYABORT; // OOM
          }
        | hint_list hint
          {
            $1->push_back($2);
            $$= $1;
          }
        ;

hint:
          index_level_hint
        | table_level_hint
        | qb_level_hint
        | qb_name_hint
        | max_execution_time_hint
        ;


max_execution_time_hint:
          MAX_EXECUTION_TIME_HINT '(' HINT_ARG_NUMBER ')'
          {
            int error;
            char *end= const_cast<char *>($3.str + $3.length);
            longlong n= my_strtoll10($3.str, &end, &error);
            if (error != 0 || end != $3.str + $3.length || n > UINT_MAX32)
            {
              scanner->syntax_warning(ER_THD(thd,
                                             ER_WARN_BAD_MAX_EXECUTION_TIME));
              $$= NULL;
            }
            else
            {
              $$= NEW_PTN PT_hint_max_execution_time(n);
              if ($$ == NULL)
                YYABORT; // OOM
            }
          }
        ;


opt_hint_param_table_list:
          /* empty */ { $$.init(thd->mem_root); }
        | hint_param_table_list
        ;

hint_param_table_list:
          hint_param_table
          {
            $$.init(thd->mem_root);
            if ($$.push_back($1))
              YYABORT; // OOM
          }
        | hint_param_table_list ',' hint_param_table
          {
            if ($1.push_back($3))
              YYABORT; // OOM
            $$= $1;
          }
        ;

opt_hint_param_table_list_empty_qb:
          /* empty */ { $$.init(thd->mem_root); }
        | hint_param_table_list_empty_qb
        ;

hint_param_table_list_empty_qb:
          hint_param_table_empty_qb
          {
            $$.init(thd->mem_root);
            if ($$.push_back($1))
              YYABORT; // OOM
          }
        | hint_param_table_list_empty_qb ',' hint_param_table_empty_qb
          {
            if ($1.push_back($3))
              YYABORT; // OOM
            $$= $1;
          }
        ;

opt_hint_param_index_list:
          /* empty */ { $$.init(thd->mem_root); }
        | hint_param_index_list
        ;

hint_param_index_list:
          hint_param_index
          {
            $$.init(thd->mem_root);
            if ($$.push_back($1))
              YYABORT; // OOM
          }
        | hint_param_index_list ',' hint_param_index
          {
            if ($1.push_back($3))
              YYABORT; // OOM
            $$= $1;
          }
        ;

hint_param_index:
          HINT_ARG_IDENT
        ;

hint_param_table_empty_qb:
          HINT_ARG_IDENT
          {
            $$.table= $1;
            $$.opt_query_block= NULL_CSTR;
          }
        ;

hint_param_table:
          HINT_ARG_IDENT opt_qb_name
          {
            $$.table= $1;
            $$.opt_query_block= $2;
          }
        ;

hint_param_table_ext:
          hint_param_table
        | HINT_ARG_QB_NAME HINT_ARG_IDENT
          {
            $$.table= $2;
            $$.opt_query_block= $1;
          }
        ;

opt_qb_name:
          /* empty */ { $$= NULL_CSTR; }
        | HINT_ARG_QB_NAME
        ;

qb_level_hint:
          SEMIJOIN_HINT '(' opt_qb_name semijoin_strategies ')'
          {
            $$= NEW_PTN PT_qb_level_hint($3, TRUE, SEMIJOIN_HINT_ENUM, $4);
            if ($$ == NULL)
              YYABORT; // OOM
          }
          |
          NO_SEMIJOIN_HINT '(' opt_qb_name semijoin_strategies ')'
          {
            $$= NEW_PTN PT_qb_level_hint($3, FALSE, SEMIJOIN_HINT_ENUM, $4);
            if ($$ == NULL)
              YYABORT; // OOM
          }
          |
          SUBQUERY_HINT '(' opt_qb_name subquery_strategy ')'
          {
            $$= NEW_PTN PT_qb_level_hint($3, TRUE, SUBQUERY_HINT_ENUM, $4);
            if ($$ == NULL)
              YYABORT; // OOM
          }
          ;

semijoin_strategies:
          /* empty */ { $$= 0; }
	| semijoin_strategy
          {
            $$= $1;
          }
        | semijoin_strategies ',' semijoin_strategy
          {
            $$= $1 | $3;
          }
        ;

semijoin_strategy:
          FIRSTMATCH_HINT      { $$= OPTIMIZER_SWITCH_FIRSTMATCH; }
        | LOOSESCAN_HINT       { $$= OPTIMIZER_SWITCH_LOOSE_SCAN; }
        | MATERIALIZATION_HINT { $$= OPTIMIZER_SWITCH_MATERIALIZATION; }
        | DUPSWEEDOUT_HINT     { $$= OPTIMIZER_SWITCH_DUPSWEEDOUT; }
        ;

subquery_strategy:
          MATERIALIZATION_HINT { $$=
                                   Item_exists_subselect::EXEC_MATERIALIZATION; }
        | INTOEXISTS_HINT      { $$= Item_exists_subselect::EXEC_EXISTS; }
        ;


table_level_hint:
          table_level_hint_type_on '(' opt_hint_param_table_list ')'
          {
            $$= NEW_PTN PT_table_level_hint(NULL_CSTR, $3, TRUE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        | table_level_hint_type_on
          '(' HINT_ARG_QB_NAME opt_hint_param_table_list_empty_qb ')'
          {
            $$= NEW_PTN PT_table_level_hint($3, $4, TRUE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        | table_level_hint_type_off '(' opt_hint_param_table_list ')'
          {
            $$= NEW_PTN PT_table_level_hint(NULL_CSTR, $3, FALSE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        | table_level_hint_type_off
          '(' HINT_ARG_QB_NAME opt_hint_param_table_list_empty_qb ')'
          {
            $$= NEW_PTN PT_table_level_hint($3, $4, FALSE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        ;

index_level_hint:
          key_level_hint_type_on
          '(' hint_param_table_ext opt_hint_param_index_list ')'
          {
            $$= NEW_PTN PT_key_level_hint($3, $4, TRUE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        | key_level_hint_type_off
          '(' hint_param_table_ext opt_hint_param_index_list ')'
          {
            $$= NEW_PTN PT_key_level_hint($3, $4, FALSE, $1);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        ;

table_level_hint_type_on:
          BKA_HINT
          {
            $$= BKA_HINT_ENUM;
          }
        | BNL_HINT
          {
            $$= BNL_HINT_ENUM;
          }
        ;

table_level_hint_type_off:
          NO_BKA_HINT
          {
            $$= BKA_HINT_ENUM;
          }
        | NO_BNL_HINT
          {
            $$= BNL_HINT_ENUM;
          }
        ;

key_level_hint_type_on:
          MRR_HINT
          {
            $$= MRR_HINT_ENUM;
          }
        | NO_RANGE_OPTIMIZATION_HINT
          {
            $$= NO_RANGE_HINT_ENUM;
          }
        ;

key_level_hint_type_off:
          NO_ICP_HINT
          {
            $$= ICP_HINT_ENUM;
          }
        | NO_MRR_HINT
          {
            $$= MRR_HINT_ENUM;
          }
        ;

qb_name_hint:
          QB_NAME_HINT '(' HINT_ARG_IDENT ')'
          {
            $$= NEW_PTN PT_hint_qb_name($3);
            if ($$ == NULL)
              YYABORT; // OOM
          }
        ;