mysql5/mysql-5.7.27/sql/sql_show_status.cc

344 lines
12 KiB
C++

/* Copyright (c) 2015, 2016 Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 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 */
#include "sql_show_status.h"
#include "sql_parse.h"
#include "sql_yacc.h"
#include "parse_tree_items.h"
#include "parse_tree_nodes.h"
#include "item_cmpfunc.h"
/**
Build a replacement query for SHOW STATUS.
When the parser accepts the following syntax:
SHOW GLOBAL STATUS
the parsed tree built for this query is in fact:
SELECT * FROM
(SELECT VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value
FROM performance_schema.global_status) global_status
Likewise, the query:
SHOW GLOBAL STATUS LIKE "<value>"
is built as:
SELECT * FROM
(SELECT VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value
FROM performance_schema.global_status) global_status
WHERE Variable_name LIKE "<value>"
Likewise, the query:
SHOW GLOBAL STATUS where <where_clause>
is built as:
SELECT * FROM
(SELECT VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value
FROM performance_schema.global_status) global_status
WHERE <where_clause>
*/
SELECT_LEX*
build_query(const POS &pos,
THD *thd,
enum_sql_command command,
const LEX_STRING& table_name,
const String *wild,
Item *where_cond)
{
/*
MAINTAINER:
This code builds a parsed tree for a query.
Write the query to build in SQL first,
then see turn_parser_debug_on() in sql_yacc.yy
to understand which grammar actions are needed to
build a parsed tree for this SQL query.
*/
static const LEX_STRING col_name= { C_STRING_WITH_LEN("VARIABLE_NAME")};
static const LEX_STRING as_name= { C_STRING_WITH_LEN("Variable_name")};
static const LEX_STRING col_value= { C_STRING_WITH_LEN("VARIABLE_VALUE")};
static const LEX_STRING as_value= { C_STRING_WITH_LEN("Value")};
static const LEX_STRING pfs= { C_STRING_WITH_LEN("performance_schema")};
static const Query_options options=
{
0, /* query_spec_options */
SELECT_LEX::SQL_CACHE_UNSPECIFIED /* sql_cache */
};
static const Select_lock_type lock_type=
{
false, /* is_set */
TL_READ, /* lock_type */
false /* is_safe_to_cache_query */
};
/* * */
Item *star= new (thd->mem_root) Item_field(pos, NULL, NULL, "*");
PT_select_item_list *item_list2;
item_list2= new (thd->mem_root) PT_select_item_list();
if (item_list2 == NULL)
return NULL;
item_list2->push_back(star);
/* SELECT * ... */
PT_select_options_and_item_list *options_and_item_list2;
options_and_item_list2= new (thd->mem_root) PT_select_options_and_item_list(options, item_list2);
if (options_and_item_list2 == NULL)
return NULL;
/*
... (SELECT VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value
FROM performance_schema.<table_name>) ...
*/
/* ... VARIABLE_NAME ... */
PTI_simple_ident_ident *ident_name;
ident_name= new (thd->mem_root) PTI_simple_ident_ident(pos, col_name);
if (ident_name == NULL)
return NULL;
/* ... VARIABLE_NAME as Variable_name ... */
PTI_expr_with_alias *expr_name;
expr_name= new (thd->mem_root) PTI_expr_with_alias(pos, ident_name, pos.cpp, as_name);
if (expr_name == NULL)
return NULL;
/* ... VARIABLE_VALUE ... */
PTI_simple_ident_ident *ident_value;
ident_value= new (thd->mem_root) PTI_simple_ident_ident(pos, col_value);
if (ident_value == NULL)
return NULL;
/* ... VARIABLE_VALUE as Value ... */
PTI_expr_with_alias *expr_value;
expr_value= new (thd->mem_root) PTI_expr_with_alias(pos, ident_value, pos.cpp, as_value);
if (expr_value == NULL)
return NULL;
/* ... VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value ... */
PT_select_item_list *item_list;
item_list= new (thd->mem_root) PT_select_item_list();
if (item_list == NULL)
return NULL;
item_list->push_back(expr_name);
item_list->push_back(expr_value);
/* SELECT VARIABLE_NAME as Variable_name, VARIABLE_VALUE as Value ... */
PT_select_options_and_item_list *options_and_item_list;
options_and_item_list= new (thd->mem_root) PT_select_options_and_item_list(options, item_list);
if (options_and_item_list == NULL)
return NULL;
/*
make_table_list() might alter the database and table name strings. Create
copies and leave the original values unaltered.
*/
/* ... performance_schema ... */
LEX_CSTRING tmp_db_name;
if (!thd->make_lex_string(&tmp_db_name, pfs.str, pfs.length, false))
return NULL;
/* ... <table_name> ... */
LEX_CSTRING tmp_table_name;
if (!thd->make_lex_string(&tmp_table_name, table_name.str, table_name.length, false))
return NULL;
/* ... performance_schema.<table_name> ... */
Table_ident *table_ident;
table_ident= new (thd->mem_root) Table_ident(tmp_db_name, tmp_table_name);
if (table_ident == NULL)
return NULL;
/* ... FROM performance_schema.<table_name> ... */
PT_table_factor_table_ident *table_factor;
table_factor= new (thd->mem_root) PT_table_factor_table_ident(table_ident, NULL, NULL, NULL);
if (table_factor == NULL)
return NULL;
PT_join_table_list *join_table_list;
join_table_list= new (thd->mem_root) PT_join_table_list(pos, table_factor);
if (join_table_list == NULL)
return NULL;
PT_table_reference_list *table_reference_list;
table_reference_list= new (thd->mem_root) PT_table_reference_list(join_table_list);
if (table_reference_list == NULL)
return NULL;
PT_table_expression *table_expression;
table_expression= new (thd->mem_root)PT_table_expression(table_reference_list,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
lock_type);
/* ... FROM (SELECT ...) ... */
PT_table_factor_select_sym *table_factor_select_sym;
table_factor_select_sym= new (thd->mem_root) PT_table_factor_select_sym(pos, NULL, options, item_list, table_expression);
if (table_factor_select_sym == NULL)
return NULL;
PT_select_derived *select_derived;
select_derived= new (thd->mem_root) PT_select_derived(pos, table_factor_select_sym);
if (select_derived == NULL)
return NULL;
PT_select_derived_union_select *select_derived_union_select;
select_derived_union_select= new (thd->mem_root) PT_select_derived_union_select(select_derived, NULL, pos);
if (select_derived_union_select == NULL)
return NULL;
/* ... derived_table ... */
LEX_STRING derived_table_name;
if (!thd->make_lex_string(&derived_table_name, table_name.str, table_name.length, false))
return NULL;
PT_table_factor_parenthesis *table_factor_parenthesis;
table_factor_parenthesis= new (thd->mem_root) PT_table_factor_parenthesis(select_derived_union_select, &derived_table_name, pos);
if (table_factor_parenthesis == NULL)
return NULL;
PT_join_table_list *join_table_list2;
join_table_list2= new (thd->mem_root) PT_join_table_list(pos, table_factor_parenthesis);
if (join_table_list2 == NULL)
return NULL;
PT_table_reference_list *table_reference_list2;
table_reference_list2= new (thd->mem_root) PT_table_reference_list(join_table_list2);
if (table_reference_list2 == NULL)
return NULL;
/* where clause */
Item *where_clause= NULL;
if (wild != NULL)
{
/* ... Variable_name ... */
PTI_simple_ident_ident *ident_name_where;
ident_name_where= new (thd->mem_root) PTI_simple_ident_ident(pos, as_name);
if (ident_name_where == NULL)
return NULL;
/* ... <value> ... */
LEX_STRING *lex_string;
lex_string= static_cast<LEX_STRING*> (thd->alloc(sizeof(LEX_STRING)));
if (lex_string == NULL)
return NULL;
lex_string->length= wild->length();
lex_string->str= thd->strmake(wild->ptr(), wild->length());
if (lex_string->str == NULL)
return NULL;
PTI_text_literal_text_string *wild_string;
wild_string= new (thd->mem_root) PTI_text_literal_text_string(pos, false, *lex_string); // TODO WL#6629 check is_7bit
if (wild_string == NULL)
return NULL;
/* ... Variable_name LIKE <value> ... */
Item_func_like *func_like;
func_like= new (thd->mem_root) Item_func_like(pos, ident_name_where, wild_string, NULL);
if (func_like == NULL)
return NULL;
/* ... WHERE Variable_name LIKE <value> ... */
where_clause= new (thd->mem_root) PTI_context<CTX_WHERE>(pos, func_like);
if (where_clause == NULL)
return NULL;
}
else
{
where_clause= where_cond;
}
/* SELECT * FROM (SELECT ...) derived_table [ WHERE Variable_name LIKE <value> ] */
/* SELECT * FROM (SELECT ...) derived_table [ WHERE <cond> ] */
PT_select_part2 *select_part2;
select_part2= new (thd->mem_root) PT_select_part2(options_and_item_list2,
NULL, /* opt_into */
table_reference_list2, /* from_clause */
where_clause, /* opt_where_clause */
NULL, /* opt_group_clause */
NULL, /* opt_having_clause */
NULL, /* opt_order_clause */
NULL, /* opt_limit_clause */
NULL, /* opt_procedure_analyse_clause */
NULL, /* opt_into */
lock_type /* opt_select_lock_type */);
if (select_part2 == NULL)
return NULL;
PT_select_init2 *select_init2;
select_init2= new (thd->mem_root) PT_select_init2(NULL, select_part2, NULL);
if (select_init2 == NULL)
return NULL;
PT_select *select;
select= new (thd->mem_root) PT_select(select_init2, SQLCOM_SELECT);
if (select == NULL)
return NULL;
LEX *lex= thd->lex;
SELECT_LEX *current_select= lex->current_select();
Parse_context pc(thd, current_select);
if (thd->is_error())
return NULL;
if (select->contextualize(&pc))
return NULL;
/* contextualize sets to COM_SELECT */
lex->sql_command= command;
return current_select;
}
SELECT_LEX*
build_show_session_status(const POS &pos, THD *thd, const String *wild, Item *where_cond)
{
static const LEX_STRING table_name= { C_STRING_WITH_LEN("session_status")};
return build_query(pos, thd, SQLCOM_SHOW_STATUS, table_name, wild, where_cond);
}
SELECT_LEX*
build_show_global_status(const POS &pos, THD *thd, const String *wild, Item *where_cond)
{
static const LEX_STRING table_name= { C_STRING_WITH_LEN("global_status")};
return build_query(pos, thd, SQLCOM_SHOW_STATUS, table_name, wild, where_cond);
}
SELECT_LEX*
build_show_session_variables(const POS &pos, THD *thd, const String *wild, Item *where_cond)
{
static const LEX_STRING table_name= { C_STRING_WITH_LEN("session_variables")};
return build_query(pos, thd, SQLCOM_SHOW_VARIABLES, table_name, wild, where_cond);
}
SELECT_LEX*
build_show_global_variables(const POS &pos, THD *thd, const String *wild, Item *where_cond)
{
static const LEX_STRING table_name= { C_STRING_WITH_LEN("global_variables")};
return build_query(pos, thd, SQLCOM_SHOW_VARIABLES, table_name, wild, where_cond);
}