mysql5/mysql-5.7.27/storage/perfschema/table_session_variables.h

111 lines
2.9 KiB
C++

/* Copyright (c) 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, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifndef TABLE_SESSION_VARIABLES_H
#define TABLE_SESSION_VARIABLES_H
/**
@file storage/perfschema/table_session_variables.h
Table SESSION_VARIABLES (declarations).
*/
#include "pfs_column_types.h"
#include "pfs_engine_table.h"
#include "pfs_instr_class.h"
#include "pfs_instr.h"
#include "table_helper.h"
#include "pfs_variable.h"
/**
@addtogroup Performance_schema_tables
@{
*/
/**
Store and retrieve table state information during queries that reinstantiate
the table object.
*/
class table_session_variables_context : public PFS_table_context
{
public:
table_session_variables_context(ulonglong hash_version, bool restore) :
PFS_table_context(hash_version, restore, THR_PFS_SV) {}
};
/**
A row of table
PERFORMANCE_SCHEMA.SESSION_VARIABLES.
*/
struct row_session_variables
{
/** Column VARIABLE_NAME. */
PFS_variable_name_row m_variable_name;
/** Column VARIABLE_VALUE. */
PFS_variable_value_row m_variable_value;
};
/** Table PERFORMANCE_SCHEMA.SESSION_VARIABLES. */
class table_session_variables : public PFS_engine_table
{
typedef PFS_simple_index pos_t;
public:
/** Table share */
static PFS_engine_table_share m_share;
static PFS_engine_table* create();
static ha_rows get_row_count();
virtual int rnd_init(bool scan);
virtual int rnd_next();
virtual int rnd_pos(const void *pos);
virtual void reset_position(void);
protected:
virtual int read_row_values(TABLE *table,
unsigned char *buf,
Field **fields,
bool read_all);
table_session_variables();
public:
~table_session_variables()
{}
protected:
void make_row(const System_variable *system_var);
private:
/** Table share lock. */
static THR_LOCK m_table_lock;
/** Fields definition. */
static TABLE_FIELD_DEF m_field_def;
/** Current THD variables. */
PFS_system_variable_cache m_sysvar_cache;
/** Current row. */
row_session_variables m_row;
/** True if the current row exists. */
bool m_row_exists;
/** Current position. */
pos_t m_pos;
/** Next position. */
pos_t m_next_pos;
/** Table context with system variable hash version. */
table_session_variables_context *m_context;
};
/** @} */
#endif