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/* 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 */
/**
@file storage/perfschema/table_session_variables.cc
Table SESSION_VARIABLES (implementation).
*/
#include "my_global.h"
#include "my_thread.h"
#include "table_session_variables.h"
#include "pfs_instr_class.h"
#include "pfs_column_types.h"
#include "pfs_column_values.h"
#include "pfs_global.h"
THR_LOCK table_session_variables::m_table_lock;
PFS_engine_table_share_state
table_session_variables::m_share_state = {
false /* m_checked */
};
PFS_engine_table_share
table_session_variables::m_share=
{
{ C_STRING_WITH_LEN("session_variables") },
&pfs_readonly_world_acl,
table_session_variables::create,
NULL, /* write_row */
NULL, /* delete_all_rows */
table_session_variables::get_row_count,
sizeof(pos_t),
&m_table_lock,
{ C_STRING_WITH_LEN("CREATE TABLE session_variables("
"VARIABLE_NAME VARCHAR(64) not null,"
"VARIABLE_VALUE VARCHAR(1024))") },
true, /* m_perpetual */
&m_share_state
};
PFS_engine_table*
table_session_variables::create(void)
{
return new table_session_variables();
}
ha_rows table_session_variables::get_row_count(void)
{
mysql_mutex_lock(&LOCK_plugin_delete);
mysql_prlock_rdlock(&LOCK_system_variables_hash);
ha_rows system_var_count= get_system_variable_hash_records();
mysql_prlock_unlock(&LOCK_system_variables_hash);
mysql_mutex_unlock(&LOCK_plugin_delete);
return system_var_count;
}
table_session_variables::table_session_variables()
: PFS_engine_table(&m_share, &m_pos),
m_sysvar_cache(false), m_row_exists(false), m_pos(0), m_next_pos(0)
{}
void table_session_variables::reset_position(void)
{
m_pos.m_index = 0;
m_next_pos.m_index = 0;
}
int table_session_variables::rnd_init(bool scan)
{
/* Build a cache of system variables for this thread. */
m_sysvar_cache.materialize_all(current_thd);
/* Record the version of the system variable hash. */
ulonglong hash_version= m_sysvar_cache.get_sysvar_hash_version();
/*
The table context holds the current version of the system variable hash.
If scan == true, then allocate a new context from mem_root and store in TLS.
If scan == false, then restore from TLS.
*/
m_context= (table_session_variables_context *)current_thd->alloc(sizeof(table_session_variables_context));
new(m_context) table_session_variables_context(hash_version, !scan);
return 0;
}
int table_session_variables::rnd_next(void)
{
for (m_pos.set_at(&m_next_pos);
m_pos.m_index < m_sysvar_cache.size();
m_pos.next())
{
if (m_sysvar_cache.is_materialized())
{
const System_variable *system_var= m_sysvar_cache.get(m_pos.m_index);
if (system_var != NULL)
{
make_row(system_var);
m_next_pos.set_after(&m_pos);
return 0;
}
}
}
return HA_ERR_END_OF_FILE;
}
int table_session_variables::rnd_pos(const void *pos)
{
/* If system variable hash changes, do nothing. */
if (!m_context->versions_match())
return HA_ERR_RECORD_DELETED;
set_position(pos);
assert(m_pos.m_index < m_sysvar_cache.size());
if (m_sysvar_cache.is_materialized())
{
const System_variable *system_var= m_sysvar_cache.get(m_pos.m_index);
if (system_var != NULL)
{
make_row(system_var);
return 0;
}
}
return HA_ERR_RECORD_DELETED;
}
void table_session_variables
::make_row(const System_variable *system_var)
{
m_row_exists= false;
if (system_var->is_null() || system_var->is_ignored())
return;
m_row.m_variable_name.make_row(system_var->m_name, system_var->m_name_length);
m_row.m_variable_value.make_row(system_var);
m_row_exists= true;
}
int table_session_variables
::read_row_values(TABLE *table,
unsigned char *buf,
Field **fields,
bool read_all)
{
Field *f;
if (unlikely(!m_row_exists))
return HA_ERR_RECORD_DELETED;
/* Set the null bits */
assert(table->s->null_bytes == 1);
buf[0]= 0;
for (; (f= *fields) ; fields++)
{
if (read_all || bitmap_is_set(table->read_set, f->field_index))
{
switch(f->field_index)
{
case 0: /* VARIABLE_NAME */
set_field_varchar_utf8(f, m_row.m_variable_name.m_str, m_row.m_variable_name.m_length);
break;
case 1: /* VARIABLE_VALUE */
m_row.m_variable_value.set_field(f);
break;
default:
assert(false);
}
}
}
return 0;
}
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