mysql5/mysql-5.7.27/sql/opt_costmodel.cc

109 lines
3.1 KiB
C++

/*
Copyright (c) 2014, 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 */
// First include (the generated) my_config.h, to get correct platform defines.
#include "my_config.h"
#include "opt_costmodel.h"
#include "opt_costconstantcache.h" // Cost_constant_cache
#include "table.h" // TABLE
extern Cost_constant_cache *cost_constant_cache;// defined in
// opt_costconstantcache.cc
Cost_model_server::~Cost_model_server()
{
if (m_cost_constants)
{
cost_constant_cache->release_cost_constants(m_cost_constants);
m_cost_constants= NULL;
}
}
void Cost_model_server::init()
{
if (m_server_cost_constants == NULL)
{
// Get the current set of cost constants
m_cost_constants= cost_constant_cache->get_cost_constants();
DBUG_ASSERT(m_cost_constants != NULL);
// Get the cost constants for server operations
m_server_cost_constants= m_cost_constants->get_server_cost_constants();
DBUG_ASSERT(m_server_cost_constants != NULL);
#if !defined(DBUG_OFF)
m_initialized= true;
#endif
}
}
void Cost_model_table::init(const Cost_model_server *cost_model_server,
const TABLE *table)
{
DBUG_ASSERT(cost_model_server != NULL);
DBUG_ASSERT(table != NULL);
m_cost_model_server= cost_model_server;
m_table= table;
// Find the cost constant object to be used for this table
m_se_cost_constants=
m_cost_model_server->get_cost_constants()->get_se_cost_constants(table);
DBUG_ASSERT(m_se_cost_constants != NULL);
#if !defined(DBUG_OFF)
m_initialized= true;
#endif
}
double Cost_model_table::page_read_cost(double pages) const
{
DBUG_ASSERT(m_initialized);
DBUG_ASSERT(pages >= 0.0);
const double in_mem= m_table->file->table_in_memory_estimate();
const double pages_in_mem= pages * in_mem;
const double pages_on_disk= pages - pages_in_mem;
DBUG_ASSERT(pages_on_disk >= 0.0);
const double cost= buffer_block_read_cost(pages_in_mem) +
io_block_read_cost(pages_on_disk);
return cost;
}
double Cost_model_table::page_read_cost_index(uint index, double pages) const
{
DBUG_ASSERT(m_initialized);
DBUG_ASSERT(pages >= 0.0);
double in_mem= m_table->file->index_in_memory_estimate(index);
const double pages_in_mem= pages * in_mem;
const double pages_on_disk= pages - pages_in_mem;
const double cost= buffer_block_read_cost(pages_in_mem) +
io_block_read_cost(pages_on_disk);
return cost;
}