external_sort.h

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/*
 * Copyright 2008 Search Solution Corporation
 * Copyright 2016 CUBRID Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */


/*
 * external_sort.h - External sorting module
 */

#ifndef _EXTERNAL_SORT_H_
#define _EXTERNAL_SORT_H_

#ident "$Id$"

#if !defined (SERVER_MODE) && !defined (SA_MODE)
#error Belongs to server module
#endif /* !defined (SERVER_MODE) && !defined (SA_MODE) */

#include "error_manager.h"
#include "query_list.h"
#include "storage_common.h"
#include "thread_compat.hpp"

#define SORT_PUT_STOP     2

#define NO_SORT_LIMIT (-1)

#define SORT_RECORD_LENGTH_SIZE (sizeof(INT64)) /* for 8byte align */
#define SORT_RECORD_LENGTH(item_p) (*((int *) ((item_p) - SORT_RECORD_LENGTH_SIZE)))

typedef enum
{
  SORT_REC_DOESNT_FIT,
  SORT_SUCCESS,
  SORT_NOMORE_RECS,
  SORT_ERROR_OCCURRED
} SORT_STATUS;

typedef enum
{
  SORT_ELIM_DUP,        /* eliminate duplicate */
  SORT_DUP          /* allow duplicate */
} SORT_DUP_OPTION;

typedef SORT_STATUS SORT_GET_FUNC (THREAD_ENTRY * thread_p, RECDES *, void *);
typedef int SORT_PUT_FUNC (THREAD_ENTRY * thread_p, const RECDES *, void *);
typedef int SORT_CMP_FUNC (const void *, const void *, void *);

typedef struct SORT_REC SORT_REC;
typedef struct SUBKEY_INFO SUBKEY_INFO;
typedef struct SORTKEY_INFO SORTKEY_INFO;
typedef struct SORT_INFO SORT_INFO;

struct SORT_REC
{
  SORT_REC *next;       /* forward link for duplicate sort_key value */
  union
  {
    /* Bread crumbs back to the original tuple, so that we can go straight there after the keys have been sorted. */
    struct
    {
      INT32 pageid;     /* Page identifier */
      INT16 volid;      /* Volume identifier */
      INT16 offset;     /* offset in page */
      char body[1];     /* sort_key body start position */
    } original;

    /*
     * The offset vector.  A value of zero for an entry means that the
     * corresponding column is null, and that there are no data bytes for
     * the column.  A non-zero entry is interpreted as the offset from
     * the *start* of the SORT_REC to the data bytes for that column.
     */
    int offset[1];
  } s;
};

struct SUBKEY_INFO
{
  /* The actual column number in the list file tuple. */
  int col;


  int permuted_col;

  TP_DOMAIN *col_dom;

  TP_DOMAIN *cmp_dom;       /* for median sorting string in different domain */

  // signature should match pr_type::data_cmpdisk_function_type
  // todo - use a function type for both sort_f and pr_type::data_cmpdisk_function_type
    DB_VALUE_COMPARE_RESULT (*sort_f) (void *tplp1, void *tplp2, TP_DOMAIN * dom, int do_coercion, int total_order,
                       int *start_col);

  /*
   * Non-zero iff the sort on this column is descending.  Factoring
   * this decision out of the actual sort function allows to use only
   * one of those guys, at no particularly great cost in performance,
   * and a big win in maintainability.
   */
  int is_desc;

  int is_nulls_first;

  bool use_cmp_dom;     /* when true, use cmp_dom to make comparing */
};

struct SORTKEY_INFO
{
  int nkeys;            /* The number of columns in use today. */
  int use_original;     /* False iff the sort keys consist of all of the input record fields, i.e., if we'll
                 * reconstruct the input records from the keys rather than look them up again in the
                 * original file. */
  SUBKEY_INFO *key;     /* Points to `default_keys' if `nkeys' <= 8; otherwise it points to malloc'ed space. */
  SUBKEY_INFO default_keys[8];  /* Default storage; this ought to work for most cases. */
  int error;            /* median domain convert errors */
};

struct SORT_INFO
{
  SORTKEY_INFO key_info;    /* All of the interesting key information. */
  QFILE_SORT_SCAN_ID *s_id; /* A SCAN_ID for the input list file.  This is stateful, and records the current
                 * location of the scan between calls to ls_sort_get_next(). */
  QFILE_LIST_ID *output_file;   /* The name of the output file.  This is where ls_sort_put_next_*() deposits its stuff.
                 */
  RECDES output_recdes;     /* A working buffer for output of tuples; used only when we're using
                 * ls_sort_put_next_short() as the output function. */
  void *extra_arg;      /* extra information supplied by the caller */
};

extern int sort_listfile (THREAD_ENTRY * thread_p, INT16 volid, int est_inp_pg_cnt, SORT_GET_FUNC * get_fn,
              void *get_arg, SORT_PUT_FUNC * put_fn, void *put_arg, SORT_CMP_FUNC * cmp_fn, void *cmp_arg,
              SORT_DUP_OPTION option, int limit, bool includes_tde_class);

#endif /* _EXTERNAL_SORT_H_ */