mariadb/storage/myisammrg/myrg_rprev.c
Michael Widenius ecbcddc03d Improved speed of thr_alarm from O(N) to O(1). thr_alarm is used to handle timeouts and kill of connections.
Fixed compiler warnings.
queues.h and queues.c are now based on the UNIREG code and thus made BSD.
Fix code to use new queue() interface. This mostly affects how you access elements in the queue.
If USE_NET_CLEAR is not set, don't clear connection from unexpected characters. This should give a speed up when doing a lot of fast queries.
Fixed some code in ma_ft_boolean_search.c that had not made it from myisam/ft_boolean_search.c


include/queues.h:
  Use UNIREG code base (BSD)
  Changed init_queue() to take all initialization arguments.
  New interface to access elements in queue
include/thr_alarm.h:
  Changed to use time_t instead of ulong (portability)
  Added index_in_queue, to be able to remove random element from queue in O(1)
mysys/queues.c:
  Use UNIREG code base (BSD)
  init_queue() and reinit_queue() now takes more initialization arguments. (No need for init_queue_ex() anymore)
  Now one can tell queue_insert() to store in the element a pointer to where element is in queue. This allows one to remove elements from queue in O(1) instead of O(N)
mysys/thr_alarm.c:
  Use new option in queue() to allow fast removal of elements.
  Do less inside LOCK_alarm mutex.
  This should give a major speed up of thr_alarm usage when there is many threads
sql/create_options.cc:
  Fixed wrong printf
sql/event_queue.cc:
  Use new queue interface()
sql/filesort.cc:
  Use new queue interface()
sql/ha_partition.cc:
  Use new queue interface()
sql/ha_partition.h:
  Fixed compiler warning
sql/item_cmpfunc.cc:
  Fixed compiler warning
sql/item_subselect.cc:
  Use new queue interface()
  Removed not used variable
sql/net_serv.cc:
  If USE_NET_CLEAR is not set, don't clear connection from unexpected characters.
  This should give a speed up when doing a lot of fast queries at the disadvantage that if there is a bug in the client protocol the connection will be dropped instead of being unnoticed.
sql/opt_range.cc:
  Use new queue interface()
  Fixed compiler warnings
sql/uniques.cc:
  Use new queue interface()
storage/maria/ma_ft_boolean_search.c:
  Copy code from myisam/ft_boolean_search.c
  Use new queue interface()
storage/maria/ma_ft_nlq_search.c:
  Use new queue interface()
storage/maria/ma_sort.c:
  Use new queue interface()
storage/maria/maria_pack.c:
  Use new queue interface()
  Use queue_fix() instead of own loop to fix queue.
storage/myisam/ft_boolean_search.c:
  Use new queue interface()
storage/myisam/ft_nlq_search.c:
  Use new queue interface()
storage/myisam/mi_test_all.sh:
  Remove temporary file from last run
storage/myisam/myisampack.c:
  Use new queue interface()
  Use queue_fix() instead of own loop to fix queue.
storage/myisam/sort.c:
  Use new queue interface()
storage/myisammrg/myrg_queue.c:
  Use new queue interface()
storage/myisammrg/myrg_rnext.c:
  Use new queue interface()
storage/myisammrg/myrg_rnext_same.c:
  Use new queue interface()
storage/myisammrg/myrg_rprev.c:
  Use new queue interface()
2010-07-16 10:33:01 +03:00

52 lines
1.5 KiB
C

/* Copyright (C) 2000-2003 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; 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "myrg_def.h"
/*
Read previous row with the same key as previous read
*/
int myrg_rprev(MYRG_INFO *info, uchar *buf, int inx)
{
int err;
MI_INFO *mi;
if (!info->current_table)
return (HA_ERR_KEY_NOT_FOUND);
/* at first, do rprev for the table found before */
if ((err=mi_rprev(info->current_table->table,NULL,inx)))
{
if (err == HA_ERR_END_OF_FILE)
{
queue_remove_top(&(info->by_key));
if (!info->by_key.elements)
return HA_ERR_END_OF_FILE;
}
else
return err;
}
else
{
/* Found here, adding to queue */
queue_top(&(info->by_key))=(uchar *)(info->current_table);
queue_replace_top(&(info->by_key));
}
/* now, mymerge's read_prev is as simple as one queue_top */
mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
return _myrg_mi_read_record(mi,buf);
}