mariadb/include/queues.h
unknown febda72f62 Fix for BUG#4177:
* Make index merge quick selects code allow perform several scans.
 * Delay additional handler objects creation till row retrieval is started.


include/queues.h:
  Added trivial queue_remove_all macro
mysql-test/r/index_merge.result:
  Testcase for BUG#4177
mysql-test/t/index_merge.test:
  Testcase for BUG#4177
sql/opt_range.cc:
  Fix for BUG#4177: 
   * For any quick select, row retrieval can be performed several times. Now all index_merge quick selects code handles such cases properly.
   * In QUICK_INDEX_MERGE_SELECT we use one handler object for all merged scans, and it was possible that in 
      destructor several cleanup functions were called 
   * Additionally
    - Removed redundant QUICK_INDEX_MERGE_SELECT members.
    - Now QUICK_ROR_*_SELECTs create additional handler objects only when row retrieval is started
      So if join optimizer chooses other access method, we don't create/delete handlers.
2004-11-21 11:51:19 +03:00

64 lines
2.2 KiB
C

/* Copyright (C) 2000 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Code for generell handling of priority Queues.
Implemention of queues from "Algoritms in C" by Robert Sedgewick.
Copyright Monty Program KB.
By monty.
*/
#ifndef _queues_h
#define _queues_h
#ifdef __cplusplus
extern "C" {
#endif
typedef struct st_queue {
byte **root;
void *first_cmp_arg;
uint elements;
uint max_elements;
uint offset_to_key; /* compare is done on element+offset */
int max_at_top; /* Set if queue_top gives max */
int (*compare)(void *, byte *,byte *);
} QUEUE;
#define queue_top(queue) ((queue)->root[1])
#define queue_element(queue,index) ((queue)->root[index+1])
#define queue_end(queue) ((queue)->root[(queue)->elements])
#define queue_replaced(queue) _downheap(queue,1)
typedef int (*queue_compare)(void *,byte *, byte *);
int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
pbool max_at_top, queue_compare compare,
void *first_cmp_arg);
int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
pbool max_at_top, queue_compare compare,
void *first_cmp_arg);
int resize_queue(QUEUE *queue, uint max_elements);
void delete_queue(QUEUE *queue);
void queue_insert(QUEUE *queue,byte *element);
byte *queue_remove(QUEUE *queue,uint idx);
#define queue_remove_all(queue) { (queue)->elements= 0; }
void _downheap(QUEUE *queue,uint idx);
void queue_fix(QUEUE *queue);
#define is_queue_inited(queue) ((queue)->root != 0)
#ifdef __cplusplus
}
#endif
#endif