mysql5/mysql-5.7.27/sql/opt_explain_traditional.h

51 lines
1.7 KiB
C++

/* Copyright (c) 2011, 2015, 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,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
#ifndef OPT_EXPLAIN_FORMAT_TRADITIONAL_INCLUDED
#define OPT_EXPLAIN_FORMAT_TRADITIONAL_INCLUDED
#include "opt_explain_format.h"
/**
Formatter for the traditional EXPLAIN output
*/
class Explain_format_traditional : public Explain_format
{
class Item_null *nil;
qep_row column_buffer; ///< buffer for the current output row
public:
Explain_format_traditional() : nil(NULL) {}
virtual bool is_hierarchical() const { return false; }
virtual bool send_headers(Query_result *result);
virtual bool begin_context(enum_parsing_context,
SELECT_LEX_UNIT *subquery,
const Explain_format_flags *flags)
{
return false;
}
virtual bool end_context(enum_parsing_context) { return false; }
virtual bool flush_entry();
virtual qep_row *entry() { return &column_buffer; }
private:
bool push_select_type(List<Item> *items);
};
#endif//OPT_EXPLAIN_FORMAT_TRADITIONAL_INCLUDED