table_read_plan.h

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 *
 *  Copyright (C) 2008-2009 Sun Microsystems, Inc.
 *
 *  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
 */

#pragma once

#include <drizzled/memory/sql_alloc.h>
#include <drizzled/util/functors.h>
#include <algorithm>

namespace drizzled {
namespace optimizer {

/*
  Table rows retrieval plan. Range optimizer creates QuickSelectInterface-derived
  objects from table read plans.
*/
class TableReadPlan : public memory::SqlAlloc
{
public:
  /*
    Plan read cost, with or without cost of full row retrieval, depending
    on plan creation parameters.
  */
  double read_cost;
  ha_rows records; /* estimate of #rows to be examined */

  /*
    If true, the scan returns rows in rowid order. This is used only for
    scans that can be both ROR and non-ROR.
  */
  bool is_ror;

  /*
    Create quick select for this plan.
    SYNOPSIS
     make_quick()
       param               Parameter from test_quick_select
       retrieve_full_rows  If true, created quick select will do full record
                           retrieval.
       parent_alloc        Memory pool to use, if any.

    NOTES
      retrieve_full_rows is ignored by some implementations.

    RETURN
      created quick select
      NULL on any error.
  */
  virtual QuickSelectInterface *make_quick(Parameter *param,
                                           bool retrieve_full_rows,
                                           memory::Root *parent_alloc= NULL) = 0;

  virtual ~TableReadPlan() {} /* Remove gcc warning */
};


/*
  Plan for a QuickRangeSelect scan.
  RangeReadPlan::make_quick ignores retrieve_full_rows parameter because
  QuickRangeSelect doesn't distinguish between 'index only' scans and full
  record retrieval scans.
*/
class RangeReadPlan : public TableReadPlan
{
public:
  SEL_ARG *key; /* set of intervals to be used in "range" method retrieval */
  uint32_t     key_idx; /* key number in Parameter::key */
  uint32_t     mrr_flags;
  uint32_t     mrr_buf_size;

  RangeReadPlan(SEL_ARG *key_arg, uint32_t idx_arg, uint32_t mrr_flags_arg)
    :
      key(key_arg),
      key_idx(idx_arg),
      mrr_flags(mrr_flags_arg)
  {}

  QuickSelectInterface *make_quick(Parameter *param, bool, memory::Root *parent_alloc);
};


/* Plan for QuickRorIntersectSelect scan. */
class RorIntersectReadPlan : public TableReadPlan
{
public:
  QuickSelectInterface *make_quick(Parameter *param,
                                   bool retrieve_full_rows,
                                   memory::Root *parent_alloc);

  /* Array of pointers to ROR range scans used in this intersection */
  RorScanInfo **first_scan;
  RorScanInfo **last_scan; /* End of the above array */
  RorScanInfo *cpk_scan;  /* Clustered PK scan, if there is one */

  bool is_covering; /* true if no row retrieval phase is necessary */
  double index_scan_costs; /* SUM(cost(index_scan)) */

};


/*
  Plan for QuickRorUnionSelect scan.
  QuickRorUnionSelect always retrieves full rows, so retrieve_full_rows
  is ignored by make_quick.
*/

class RorUnionReadPlan : public TableReadPlan
{
public:
  QuickSelectInterface *make_quick(Parameter *param,
                                   bool retrieve_full_rows,
                                   memory::Root *parent_alloc);
  TableReadPlan **first_ror; /* array of ptrs to plans for merged scans */
  TableReadPlan **last_ror;  /* end of the above array */
};


/*
  Plan for QuickIndexMergeSelect scan.
  QuickRorIntersectSelect always retrieves full rows, so retrieve_full_rows
  is ignored by make_quick.
*/

class IndexMergeReadPlan : public TableReadPlan
{
public:
  QuickSelectInterface *make_quick(Parameter *param,
                                   bool retrieve_full_rows,
                                   memory::Root *parent_alloc);
  RangeReadPlan **range_scans; /* array of ptrs to plans of merged scans */
  RangeReadPlan **range_scans_end; /* end of the array */
};


/*
  Plan for a QuickGroupMinMaxSelect scan.
*/

class GroupMinMaxReadPlan : public TableReadPlan
{
private:
  bool have_min;
  bool have_max;
  KeyPartInfo *min_max_arg_part;
  uint32_t group_prefix_len;
  uint32_t used_key_parts;
  uint32_t group_key_parts;
  KeyInfo *index_info;
  uint32_t index;
  uint32_t key_infix_len;
  unsigned char key_infix[MAX_KEY_LENGTH];
  SEL_TREE *range_tree; /* Represents all range predicates in the query. */
  SEL_ARG *index_tree; /* The SEL_ARG sub-tree corresponding to index_info. */
  uint32_t param_idx; /* Index of used key in param->key. */
  /* Number of records selected by the ranges in index_tree. */
public:
  ha_rows quick_prefix_records;

public:
  GroupMinMaxReadPlan(bool have_min_arg,
                      bool have_max_arg,
                      KeyPartInfo *min_max_arg_part_arg,
                      uint32_t group_prefix_len_arg,
                      uint32_t used_key_parts_arg,
                      uint32_t group_key_parts_arg,
                      KeyInfo *index_info_arg,
                      uint32_t index_arg,
                      uint32_t key_infix_len_arg,
                      unsigned char *key_infix_arg,
                      SEL_TREE *tree_arg,
                      SEL_ARG *index_tree_arg,
                      uint32_t param_idx_arg,
                      ha_rows quick_prefix_records_arg)
    :
      have_min(have_min_arg),
      have_max(have_max_arg),
      min_max_arg_part(min_max_arg_part_arg),
      group_prefix_len(group_prefix_len_arg),
      used_key_parts(used_key_parts_arg),
      group_key_parts(group_key_parts_arg),
      index_info(index_info_arg),
      index(index_arg),
      key_infix_len(key_infix_len_arg),
      range_tree(tree_arg),
      index_tree(index_tree_arg),
      param_idx(param_idx_arg),
      quick_prefix_records(quick_prefix_records_arg)
    {
      if (key_infix_len)
        memcpy(this->key_infix, key_infix_arg, key_infix_len);
    }

  QuickSelectInterface *make_quick(Parameter *param,
                                   bool retrieve_full_rows,
                                   memory::Root *parent_alloc);
};


} /* namespace optimizer */

} /* namespace drizzled */