mi_delete.c 27.2 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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 */

/* Remove a row from a MyISAM table */

#include "fulltext.h"
#include "rt_index.h"

#ifdef	__WIN__
#include <errno.h>
#endif

static int d_search(MI_INFO *info,MI_KEYDEF *keyinfo,uint comp_flag,
                    uchar *key,uint key_length,my_off_t page,uchar *anc_buff);
static int del(MI_INFO *info,MI_KEYDEF *keyinfo,uchar *key,uchar *anc_buff,
	       my_off_t leaf_page,uchar *leaf_buff,uchar *keypos,
	       my_off_t next_block,uchar *ret_key);
static int underflow(MI_INFO *info,MI_KEYDEF *keyinfo,uchar *anc_buff,
		     my_off_t leaf_page,uchar *leaf_buff,uchar *keypos);
static uint remove_key(MI_KEYDEF *keyinfo,uint nod_flag,uchar *keypos,
		       uchar *lastkey,uchar *page_end,
		       my_off_t *next_block);
static int _mi_ck_real_delete(register MI_INFO *info,MI_KEYDEF *keyinfo,
			      uchar *key, uint key_length, my_off_t *root);


int mi_delete(MI_INFO *info,const byte *record)
{
  uint i;
  uchar *old_key;
  int save_errno;
  char lastpos[8];

  MYISAM_SHARE *share=info->s;
  DBUG_ENTER("mi_delete");

	/* Test if record is in datafile */

  if (!(info->update & HA_STATE_AKTIV))
  {
    DBUG_RETURN(my_errno=HA_ERR_KEY_NOT_FOUND);	/* No database read */
  }
  if (share->options & HA_OPTION_READ_ONLY_DATA)
  {
    DBUG_RETURN(my_errno=EACCES);
  }
  if (_mi_readinfo(info,F_WRLCK,1))
    DBUG_RETURN(my_errno);
  if (info->s->calc_checksum)
    info->checksum=(*info->s->calc_checksum)(info,record);
  if ((*share->compare_record)(info,record))
    goto err;				/* Error on read-check */

  if (_mi_mark_file_changed(info))
    goto err;

	/* Remove all keys from the .ISAM file */

  old_key=info->lastkey2;
  for (i=0 ; i < share->base.keys ; i++ )
  {
    if (((ulonglong) 1 << i) & info->s->state.key_map)
    {
      info->s->keyinfo[i].version++;
      if (info->s->keyinfo[i].flag & HA_FULLTEXT )
      {
        if (_mi_ft_del(info,i,(char*) old_key,record,info->lastpos))
          goto err;
      }
      else
      {
        if (info->s->keyinfo[i].ck_delete(info,i,old_key,
                _mi_make_key(info,i,old_key,record,info->lastpos)))
          goto err;
      }
    }
  }

  if ((*share->delete_record)(info))
    goto err;				/* Remove record from database */
  info->s->state.checksum-=info->checksum;

  info->update= HA_STATE_CHANGED+HA_STATE_DELETED+HA_STATE_ROW_CHANGED;
  info->state->records--;

  mi_sizestore(lastpos,info->lastpos);
  myisam_log_command(MI_LOG_DELETE,info,(byte*) lastpos,sizeof(lastpos),0);
  VOID(_mi_writeinfo(info,WRITEINFO_UPDATE_KEYFILE));
  allow_break();			/* Allow SIGHUP & SIGINT */
  if (info->invalidator != 0)
  {
    DBUG_PRINT("info", ("invalidator... '%s' (delete)", info->filename));
    (*info->invalidator)(info->filename);
    info->invalidator=0;
  }
  DBUG_RETURN(0);

err:
  save_errno=my_errno;
  mi_sizestore(lastpos,info->lastpos);
  myisam_log_command(MI_LOG_DELETE,info,(byte*) lastpos, sizeof(lastpos),0);
  if (save_errno != HA_ERR_RECORD_CHANGED)
    mi_mark_crashed(info);		/* mark table crashed */
  VOID(_mi_writeinfo(info,WRITEINFO_UPDATE_KEYFILE));
  info->update|=HA_STATE_WRITTEN;	/* Buffer changed */
  allow_break();			/* Allow SIGHUP & SIGINT */
  my_errno=save_errno;
  if (save_errno == HA_ERR_KEY_NOT_FOUND)
    my_errno=HA_ERR_CRASHED;

  DBUG_RETURN(my_errno);
} /* mi_delete */


	/* Remove a key from the btree index */

int _mi_ck_delete(register MI_INFO *info, uint keynr, uchar *key,
		  uint key_length)
{
  return _mi_ck_real_delete(info, info->s->keyinfo+keynr, key, key_length,
                            &info->s->state.key_root[keynr]);
} /* _mi_ck_delete */


static int _mi_ck_real_delete(register MI_INFO *info, MI_KEYDEF *keyinfo,
			      uchar *key, uint key_length, my_off_t *root)
{
  int error;
  uint nod_flag;
  my_off_t old_root;
  uchar *root_buff;
  DBUG_ENTER("_mi_ck_real_delete");

  if ((old_root=*root) == HA_OFFSET_ERROR)
  {
    DBUG_RETURN(my_errno=HA_ERR_CRASHED);
  }
  if (!(root_buff= (uchar*) my_alloca((uint) keyinfo->block_length+
				      MI_MAX_KEY_BUFF*2)))
  {
    DBUG_PRINT("error",("Couldn't allocate memory"));
    DBUG_RETURN(my_errno=ENOMEM);
  }
  DBUG_PRINT("info",("root_page: %ld",old_root));
  if (!_mi_fetch_keypage(info,keyinfo,old_root,root_buff,0))
  {
    error= -1;
    goto err;
  }
  if ((error=d_search(info,keyinfo,
                      (keyinfo->flag & HA_FULLTEXT ? SEARCH_FIND
                                                   : SEARCH_SAME),
                       key,key_length,old_root,root_buff)) >0)
  {
    if (error == 2)
    {
      DBUG_PRINT("test",("Enlarging of root when deleting"));
      error=_mi_enlarge_root(info,keyinfo,key,root);
    }
    else /* error == 1 */
    {
      if (mi_getint(root_buff) <= (nod_flag=mi_test_if_nod(root_buff))+3)
      {
	error=0;
	if (nod_flag)
	  *root=_mi_kpos(nod_flag,root_buff+2+nod_flag);
	else
	  *root=HA_OFFSET_ERROR;
	if (_mi_dispose(info,keyinfo,old_root))
	  error= -1;
      }
      else
	error=_mi_write_keypage(info,keyinfo,old_root,root_buff);
    }
  }
err:
  my_afree((gptr) root_buff);
  DBUG_PRINT("exit",("Return: %d",error));
  DBUG_RETURN(error);
} /* _mi_ck_real_delete */


	/*
	** Remove key below key root
	** Return values:
	** 1 if there are less buffers;  In this case anc_buff is not saved
	** 2 if there are more buffers
	** -1 on errors
	*/

static int d_search(register MI_INFO *info, register MI_KEYDEF *keyinfo,
                    uint comp_flag, uchar *key, uint key_length,
                    my_off_t page, uchar *anc_buff)
{
  int flag,ret_value,save_flag;
  uint length,nod_flag,search_key_length;
  my_bool last_key;
  uchar *leaf_buff,*keypos;
  my_off_t leaf_page,next_block;
  uchar lastkey[MI_MAX_KEY_BUFF];
  DBUG_ENTER("d_search");
  DBUG_DUMP("page",(byte*) anc_buff,mi_getint(anc_buff));

  search_key_length= (comp_flag & SEARCH_FIND) ? key_length : USE_WHOLE_KEY;
  flag=(*keyinfo->bin_search)(info,keyinfo,anc_buff,key, search_key_length,
                              comp_flag, &keypos, lastkey, &last_key);
  if (flag == MI_FOUND_WRONG_KEY)
  {
    DBUG_PRINT("error",("Found wrong key"));
    DBUG_RETURN(-1);
  }
  nod_flag=mi_test_if_nod(anc_buff);

  if (!flag && keyinfo->flag & HA_FULLTEXT)
  {
    uint off;
    int  subkeys;

    get_key_full_length_rdonly(off, lastkey);
    subkeys=ft_sintXkorr(lastkey+off);
    comp_flag=SEARCH_SAME;
    if (subkeys >= 0)
    {
      /* normal word, one-level tree structure */
      DBUG_PRINT("info",("FT1"));
      flag=(*keyinfo->bin_search)(info,keyinfo,anc_buff,key,USE_WHOLE_KEY,
                                  comp_flag, &keypos, lastkey, &last_key);
      /* fall through to normal delete */
    }
    else
    {
      /* popular word. two-level tree. going down */
      uint tmp_key_length;
      my_off_t root;
      uchar *kpos=keypos;

      tmp_key_length=(*keyinfo->get_key)(keyinfo,nod_flag,&kpos,lastkey);
      root=_mi_dpos(info,nod_flag,kpos);
      if (subkeys == -1)
      {
        /* the last entry in sub-tree */
        DBUG_PRINT("info",("FT2: the last entry"));
        _mi_dispose(info, keyinfo, root);
        /* fall through to normal delete */
      }
      else
      {
        DBUG_PRINT("info",("FT2: going down"));
        keyinfo=&info->s->ft2_keyinfo;
        kpos-=keyinfo->keylength; /* we'll modify key entry 'in vivo' */
        key+=off;
        ret_value=_mi_ck_real_delete(info, &info->s->ft2_keyinfo,
            key, HA_FT_WLEN, &root);
        _mi_dpointer(info, kpos+HA_FT_WLEN, root);
        subkeys++;
        ft_intXstore(kpos, subkeys);
        if (!ret_value)
          ret_value=_mi_write_keypage(info,keyinfo,page,anc_buff);
        DBUG_PRINT("exit",("Return: %d",ret_value));
        DBUG_RETURN(ret_value);
      }
    }
  }
  leaf_buff=0;
  LINT_INIT(leaf_page);
  if (nod_flag)
  {
    leaf_page=_mi_kpos(nod_flag,keypos);
    if (!(leaf_buff= (uchar*) my_alloca((uint) keyinfo->block_length+
					MI_MAX_KEY_BUFF*2)))
    {
      DBUG_PRINT("error",("Couldn't allocate memory"));
      my_errno=ENOMEM;
      DBUG_PRINT("exit",("Return: %d",-1));
      DBUG_RETURN(-1);
    }
    if (!_mi_fetch_keypage(info,keyinfo,leaf_page,leaf_buff,0))
      goto err;
  }

  if (flag != 0)
  {
    if (!nod_flag)
    {
      DBUG_PRINT("error",("Didn't find key"));
      my_errno=HA_ERR_CRASHED;		/* This should newer happend */
      goto err;
    }
    save_flag=0;
    ret_value=d_search(info,keyinfo,comp_flag,key,key_length,
                       leaf_page,leaf_buff);
  }
  else
  {						/* Found key */
    uint tmp;
    length=mi_getint(anc_buff);
    tmp=remove_key(keyinfo,nod_flag,keypos,lastkey,anc_buff+length,
		   &next_block);
    if (tmp == 0)
    {
      DBUG_PRINT("exit",("Return: %d",0));
      DBUG_RETURN(0);
    }
    length-= tmp;

    mi_putint(anc_buff,length,nod_flag);
    if (!nod_flag)
    {						/* On leaf page */
      if (_mi_write_keypage(info,keyinfo,page,anc_buff))
      {
        DBUG_PRINT("exit",("Return: %d",-1));
	DBUG_RETURN(-1);
      }
      /* Page will be update later if we return 1 */
      DBUG_RETURN(test(length <= (info->quick_mode ? MI_MIN_KEYBLOCK_LENGTH :
				  (uint) keyinfo->underflow_block_length)));
    }
    save_flag=1;
    ret_value=del(info,keyinfo,key,anc_buff,leaf_page,leaf_buff,keypos,
		  next_block,lastkey);
  }
  if (ret_value >0)
  {
    save_flag=1;
    if (ret_value == 1)
      ret_value= underflow(info,keyinfo,anc_buff,leaf_page,leaf_buff,keypos);
    else
    {				/* This happens only with packed keys */
      DBUG_PRINT("test",("Enlarging of key when deleting"));
      if (!_mi_get_last_key(info,keyinfo,anc_buff,lastkey,keypos,&length))
      {
	goto err;
      }
      ret_value=_mi_insert(info,keyinfo,key,anc_buff,keypos,lastkey,
			   (uchar*) 0,(uchar*) 0,(my_off_t) 0,(my_bool) 0);
    }
  }
  if (ret_value == 0 && mi_getint(anc_buff) > keyinfo->block_length)
  {
    save_flag=1;
    ret_value=_mi_split_page(info,keyinfo,key,anc_buff,lastkey,0) | 2;
  }
  if (save_flag && ret_value != 1)
    ret_value|=_mi_write_keypage(info,keyinfo,page,anc_buff);
  else
  {
    DBUG_DUMP("page",(byte*) anc_buff,mi_getint(anc_buff));
  }
  my_afree((byte*) leaf_buff);
  DBUG_PRINT("exit",("Return: %d",ret_value));
  DBUG_RETURN(ret_value);
err:
  my_afree((byte*) leaf_buff);
  DBUG_PRINT("exit",("Error: %d",my_errno));
  DBUG_RETURN (-1);
} /* d_search */


	/* Remove a key that has a page-reference */

static int del(register MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *key,
	       uchar *anc_buff, my_off_t leaf_page, uchar *leaf_buff,
	       uchar *keypos,		/* Pos to where deleted key was */
	       my_off_t next_block,
	       uchar *ret_key)		/* key before keypos in anc_buff */
{
  int ret_value,length;
  uint a_length,nod_flag,tmp;
  my_off_t next_page;
  uchar keybuff[MI_MAX_KEY_BUFF],*endpos,*next_buff,*key_start, *prev_key;
  MYISAM_SHARE *share=info->s;
  MI_KEY_PARAM s_temp;
  DBUG_ENTER("del");
  DBUG_PRINT("enter",("leaf_page: %ld   keypos: %lx",leaf_page,keypos));
  DBUG_DUMP("leaf_buff",(byte*) leaf_buff,mi_getint(leaf_buff));

  endpos=leaf_buff+mi_getint(leaf_buff);
  if (!(key_start=_mi_get_last_key(info,keyinfo,leaf_buff,keybuff,endpos,
				   &tmp)))
    DBUG_RETURN(-1);

  if ((nod_flag=mi_test_if_nod(leaf_buff)))
  {
    next_page= _mi_kpos(nod_flag,endpos);
    if (!(next_buff= (uchar*) my_alloca((uint) keyinfo->block_length+
					MI_MAX_KEY_BUFF*2)))
      DBUG_RETURN(-1);
    if (!_mi_fetch_keypage(info,keyinfo,next_page,next_buff,0))
      ret_value= -1;
    else
    {
      DBUG_DUMP("next_page",(byte*) next_buff,mi_getint(next_buff));
      if ((ret_value=del(info,keyinfo,key,anc_buff,next_page,next_buff,
			 keypos,next_block,ret_key)) >0)
      {
	endpos=leaf_buff+mi_getint(leaf_buff);
	if (ret_value == 1)
	{
	  ret_value=underflow(info,keyinfo,leaf_buff,next_page,
			      next_buff,endpos);
	  if (ret_value == 0 && mi_getint(leaf_buff) > keyinfo->block_length)
	  {
	    ret_value=_mi_split_page(info,keyinfo,key,leaf_buff,ret_key,0) | 2;
	  }
	}
	else
	{
	  DBUG_PRINT("test",("Inserting of key when deleting"));
	  if (_mi_get_last_key(info,keyinfo,leaf_buff,keybuff,endpos,
				&tmp))
	    goto err;
	  ret_value=_mi_insert(info,keyinfo,key,leaf_buff,endpos,keybuff,
			       (uchar*) 0,(uchar*) 0,(my_off_t) 0,0);
	}
      }
      if (_mi_write_keypage(info,keyinfo,leaf_page,leaf_buff))
	goto err;
    }
    my_afree((byte*) next_buff);
    DBUG_RETURN(ret_value);
  }

	/* Remove last key from leaf page */

  mi_putint(leaf_buff,key_start-leaf_buff,nod_flag);
  if (_mi_write_keypage(info,keyinfo,leaf_page,leaf_buff))
    goto err;

	/* Place last key in ancestor page on deleted key position */

  a_length=mi_getint(anc_buff);
  endpos=anc_buff+a_length;
  if (keypos != anc_buff+2+share->base.key_reflength &&
      !_mi_get_last_key(info,keyinfo,anc_buff,ret_key,keypos,&tmp))
    goto err;
  prev_key=(keypos == anc_buff+2+share->base.key_reflength ?
	    0 : ret_key);
  length=(*keyinfo->pack_key)(keyinfo,share->base.key_reflength,
			      keypos == endpos ? (uchar*) 0 : keypos,
			      prev_key, prev_key,
			      keybuff,&s_temp);
  if (length > 0)
    bmove_upp((byte*) endpos+length,(byte*) endpos,(uint) (endpos-keypos));
  else
    bmove(keypos,keypos-length, (int) (endpos-keypos)+length);
  (*keyinfo->store_key)(keyinfo,keypos,&s_temp);
  /* Save pointer to next leaf */
  if (!(*keyinfo->get_key)(keyinfo,share->base.key_reflength,&keypos,ret_key))
    goto err;
  _mi_kpointer(info,keypos - share->base.key_reflength,next_block);
  mi_putint(anc_buff,a_length+length,share->base.key_reflength);

  DBUG_RETURN( mi_getint(leaf_buff) <=
	       (info->quick_mode ? MI_MIN_KEYBLOCK_LENGTH :
		(uint) keyinfo->underflow_block_length));
err:
  DBUG_RETURN(-1);
} /* del */


	/* Balances adjacent pages if underflow occours */

static int underflow(register MI_INFO *info, register MI_KEYDEF *keyinfo,
		     uchar *anc_buff,
		     my_off_t leaf_page,/* Ancestor page and underflow page */
		     uchar *leaf_buff,
		     uchar *keypos)	/* Position to pos after key */
{
  int t_length;
  uint length,anc_length,buff_length,leaf_length,p_length,s_length,nod_flag,
       key_reflength,key_length;
  my_off_t next_page;
  uchar anc_key[MI_MAX_KEY_BUFF],leaf_key[MI_MAX_KEY_BUFF],
        *buff,*endpos,*next_keypos,*anc_pos,*half_pos,*temp_pos,*prev_key,
        *after_key;
  MI_KEY_PARAM s_temp;
  MYISAM_SHARE *share=info->s;
  DBUG_ENTER("underflow");
  DBUG_PRINT("enter",("leaf_page: %ld   keypos: %lx",(long) leaf_page,keypos));
  DBUG_DUMP("anc_buff",(byte*) anc_buff,mi_getint(anc_buff));
  DBUG_DUMP("leaf_buff",(byte*) leaf_buff,mi_getint(leaf_buff));

  buff=info->buff;
  info->buff_used=1;
  next_keypos=keypos;
  nod_flag=mi_test_if_nod(leaf_buff);
  p_length=nod_flag+2;
  anc_length=mi_getint(anc_buff);
  leaf_length=mi_getint(leaf_buff);
  key_reflength=share->base.key_reflength;
  if (info->s->keyinfo+info->lastinx == keyinfo)
    info->page_changed=1;

  if ((keypos < anc_buff+anc_length && (info->state->records & 1)) ||
      keypos == anc_buff+2+key_reflength)
  {					/* Use page right of anc-page */
    DBUG_PRINT("test",("use right page"));

    if (keyinfo->flag & HA_BINARY_PACK_KEY)
    {
      if (!(next_keypos=_mi_get_key(info, keyinfo,
				    anc_buff, buff, keypos, &length)))
	goto err;
    }
    else
    {
      /* Got to end of found key */
      buff[0]=buff[1]=0;	/* Avoid length error check if packed key */
      if (!(*keyinfo->get_key)(keyinfo,key_reflength,&next_keypos,
			       buff))
      goto err;
    }
    next_page= _mi_kpos(key_reflength,next_keypos);
    if (!_mi_fetch_keypage(info,keyinfo,next_page,buff,0))
      goto err;
    buff_length=mi_getint(buff);
    DBUG_DUMP("next",(byte*) buff,buff_length);

    /* find keys to make a big key-page */
    bmove((byte*) next_keypos-key_reflength,(byte*) buff+2,
	  key_reflength);
    if (!_mi_get_last_key(info,keyinfo,anc_buff,anc_key,next_keypos,&length)
	|| !_mi_get_last_key(info,keyinfo,leaf_buff,leaf_key,
			     leaf_buff+leaf_length,&length))
      goto err;

    /* merge pages and put parting key from anc_buff between */
    prev_key=(leaf_length == p_length ? (uchar*) 0 : leaf_key);
    t_length=(*keyinfo->pack_key)(keyinfo,nod_flag,buff+p_length,
				  prev_key, prev_key,
				  anc_key, &s_temp);
    length=buff_length-p_length;
    endpos=buff+length+leaf_length+t_length;
    /* buff will always be larger than before !*/
    bmove_upp((byte*) endpos, (byte*) buff+buff_length,length);
    memcpy((byte*) buff, (byte*) leaf_buff,(size_t) leaf_length);
    (*keyinfo->store_key)(keyinfo,buff+leaf_length,&s_temp);
    buff_length=(uint) (endpos-buff);
    mi_putint(buff,buff_length,nod_flag);

    /* remove key from anc_buff */

    s_length=remove_key(keyinfo,key_reflength,keypos,anc_key,
			anc_buff+anc_length,(my_off_t *) 0);
    if (!s_length)
      goto err;
    anc_length-=s_length;
    mi_putint(anc_buff,anc_length,key_reflength);

    if (buff_length <= keyinfo->block_length)
    {						/* Keys in one page */
      memcpy((byte*) leaf_buff,(byte*) buff,(size_t) buff_length);
      if (_mi_dispose(info,keyinfo,next_page))
       goto err;
    }
    else
    {						/* Page is full */
      endpos=anc_buff+anc_length;
      DBUG_PRINT("test",("anc_buff: %lx  endpos: %lx",anc_buff,endpos));
      if (keypos != anc_buff+2+key_reflength &&
	  !_mi_get_last_key(info,keyinfo,anc_buff,anc_key,keypos,&length))
	goto err;
      if (!(half_pos=_mi_find_half_pos(nod_flag, keyinfo, buff, leaf_key,
				       &key_length, &after_key)))
	goto err;
      length=(uint) (half_pos-buff);
      memcpy((byte*) leaf_buff,(byte*) buff,(size_t) length);
      mi_putint(leaf_buff,length,nod_flag);

      /* Correct new keypointer to leaf_page */
      half_pos=after_key;
      _mi_kpointer(info,leaf_key+key_length,next_page);
      /* Save key in anc_buff */
      prev_key=(keypos == anc_buff+2+key_reflength ? (uchar*) 0 : anc_key),
      t_length=(*keyinfo->pack_key)(keyinfo,key_reflength,
				    (keypos == endpos ? (uchar*) 0 :
				     keypos),
				    prev_key, prev_key,
				    leaf_key, &s_temp);
      if (t_length >= 0)
	bmove_upp((byte*) endpos+t_length,(byte*) endpos,
		  (uint) (endpos-keypos));
      else
	bmove(keypos,keypos-t_length,(uint) (endpos-keypos)+t_length);
      (*keyinfo->store_key)(keyinfo,keypos,&s_temp);
      mi_putint(anc_buff,(anc_length+=t_length),key_reflength);

	/* Store key first in new page */
      if (nod_flag)
	bmove((byte*) buff+2,(byte*) half_pos-nod_flag,(size_t) nod_flag);
      if (!(*keyinfo->get_key)(keyinfo,nod_flag,&half_pos,leaf_key))
	goto err;
      t_length=(int) (*keyinfo->pack_key)(keyinfo, nod_flag, (uchar*) 0,
					  (uchar*) 0, (uchar *) 0,
					  leaf_key, &s_temp);
      /* t_length will always be > 0 for a new page !*/
      length=(uint) ((buff+mi_getint(buff))-half_pos);
      bmove((byte*) buff+p_length+t_length,(byte*) half_pos,(size_t) length);
      (*keyinfo->store_key)(keyinfo,buff+p_length,&s_temp);
      mi_putint(buff,length+t_length+p_length,nod_flag);

      if (_mi_write_keypage(info,keyinfo,next_page,buff))
	goto err;
    }
    if (_mi_write_keypage(info,keyinfo,leaf_page,leaf_buff))
      goto err;
    DBUG_RETURN(anc_length <= ((info->quick_mode ? MI_MIN_BLOCK_LENGTH :
				(uint) keyinfo->underflow_block_length)));
  }

  DBUG_PRINT("test",("use left page"));

  keypos=_mi_get_last_key(info,keyinfo,anc_buff,anc_key,keypos,&length);
  if (!keypos)
    goto err;
  next_page= _mi_kpos(key_reflength,keypos);
  if (!_mi_fetch_keypage(info,keyinfo,next_page,buff,0))
      goto err;
  buff_length=mi_getint(buff);
  endpos=buff+buff_length;
  DBUG_DUMP("prev",(byte*) buff,buff_length);

  /* find keys to make a big key-page */
  bmove((byte*) next_keypos - key_reflength,(byte*) leaf_buff+2,
	key_reflength);
  next_keypos=keypos;
  if (!(*keyinfo->get_key)(keyinfo,key_reflength,&next_keypos,
			   anc_key))
    goto err;
  if (!_mi_get_last_key(info,keyinfo,buff,leaf_key,endpos,&length))
    goto err;

  /* merge pages and put parting key from anc_buff between */
  prev_key=(leaf_length == p_length ? (uchar*) 0 : leaf_key);
  t_length=(*keyinfo->pack_key)(keyinfo,nod_flag,
				(leaf_length == p_length ?
                                 (uchar*) 0 : leaf_buff+p_length),
				prev_key, prev_key,
				anc_key, &s_temp);
  if (t_length >= 0)
    bmove((byte*) endpos+t_length,(byte*) leaf_buff+p_length,
	    (size_t) (leaf_length-p_length));
  else						/* We gained space */
    bmove((byte*) endpos,(byte*) leaf_buff+((int) p_length-t_length),
	  (size_t) (leaf_length-p_length+t_length));

  (*keyinfo->store_key)(keyinfo,endpos,&s_temp);
  buff_length=buff_length+leaf_length-p_length+t_length;
  mi_putint(buff,buff_length,nod_flag);

  /* remove key from anc_buff */
  s_length=remove_key(keyinfo,key_reflength,keypos,anc_key,
		      anc_buff+anc_length,(my_off_t *) 0);
  if (!s_length)
    goto err;
  anc_length-=s_length;
  mi_putint(anc_buff,anc_length,key_reflength);

  if (buff_length <= keyinfo->block_length)
  {						/* Keys in one page */
    if (_mi_dispose(info,keyinfo,leaf_page))
      goto err;
  }
  else
  {						/* Page is full */
    if (keypos == anc_buff+2+key_reflength)
      anc_pos=0;				/* First key */
    else if (!_mi_get_last_key(info,keyinfo,anc_buff,anc_pos=anc_key,keypos,
			       &length))
      goto err;
    endpos=_mi_find_half_pos(nod_flag,keyinfo,buff,leaf_key,
			     &key_length, &half_pos);
    if (!endpos)
      goto err;
    _mi_kpointer(info,leaf_key+key_length,leaf_page);
    /* Save key in anc_buff */
    DBUG_DUMP("anc_buff",(byte*) anc_buff,anc_length);
    DBUG_DUMP("key_to_anc",(byte*) leaf_key,key_length);

    temp_pos=anc_buff+anc_length;
    t_length=(*keyinfo->pack_key)(keyinfo,key_reflength,
				  keypos == temp_pos ? (uchar*) 0
				  : keypos,
				  anc_pos, anc_pos,
				  leaf_key,&s_temp);
    if (t_length > 0)
      bmove_upp((byte*) temp_pos+t_length,(byte*) temp_pos,
		(uint) (temp_pos-keypos));
    else
      bmove(keypos,keypos-t_length,(uint) (temp_pos-keypos)+t_length);
    (*keyinfo->store_key)(keyinfo,keypos,&s_temp);
    mi_putint(anc_buff,(anc_length+=t_length),key_reflength);

    /* Store first key on new page */
    if (nod_flag)
      bmove((byte*) leaf_buff+2,(byte*) half_pos-nod_flag,(size_t) nod_flag);
    if (!(length=(*keyinfo->get_key)(keyinfo,nod_flag,&half_pos,leaf_key)))
      goto err;
    DBUG_DUMP("key_to_leaf",(byte*) leaf_key,length);
    t_length=(*keyinfo->pack_key)(keyinfo,nod_flag, (uchar*) 0,
				  (uchar*) 0, (uchar*) 0, leaf_key, &s_temp);
    length=(uint) ((buff+buff_length)-half_pos);
    DBUG_PRINT("info",("t_length: %d  length: %d",t_length,(int) length));
    bmove((byte*) leaf_buff+p_length+t_length,(byte*) half_pos,
	  (size_t) length);
    (*keyinfo->store_key)(keyinfo,leaf_buff+p_length,&s_temp);
    mi_putint(leaf_buff,length+t_length+p_length,nod_flag);
    if (_mi_write_keypage(info,keyinfo,leaf_page,leaf_buff))
      goto err;
    mi_putint(buff,endpos-buff,nod_flag);
  }
  if (_mi_write_keypage(info,keyinfo,next_page,buff))
    goto err;
  DBUG_RETURN(anc_length <= (uint) keyinfo->block_length/2);
err:
  DBUG_RETURN(-1);
} /* underflow */


	/*
	  remove a key from packed buffert
	  The current code doesn't handle the case that the next key may be
	  packed better against the previous key if there is a case difference
	  returns how many chars was removed or 0 on error
	*/

static uint remove_key(MI_KEYDEF *keyinfo, uint nod_flag,
		       uchar *keypos,	/* Where key starts */
		       uchar *lastkey,	/* key to be removed */
		       uchar *page_end, /* End of page */
		       my_off_t *next_block)	/* ptr to next block */
{
  int s_length;
  uchar *start;
  DBUG_ENTER("remove_key");
  DBUG_PRINT("enter",("keypos: %lx  page_end: %lx",keypos,page_end));

  start=keypos;
  if (!(keyinfo->flag &
	(HA_PACK_KEY | HA_SPACE_PACK_USED | HA_VAR_LENGTH_KEY |
	 HA_BINARY_PACK_KEY)))
  {
    s_length=(int) (keyinfo->keylength+nod_flag);
    if (next_block && nod_flag)
      *next_block= _mi_kpos(nod_flag,keypos+s_length);
  }
  else
  {					 /* Let keypos point at next key */
    /* Calculate length of key */
    if (!(*keyinfo->get_key)(keyinfo,nod_flag,&keypos,lastkey))
      DBUG_RETURN(0);				/* Error */
    if (next_block && nod_flag)
      *next_block= _mi_kpos(nod_flag,keypos);
    s_length=(int) (keypos-start);
    if (keypos != page_end)
    {
      if (keyinfo->flag & HA_BINARY_PACK_KEY)
      {
	uchar *old_key=start;
	uint next_length,prev_length,prev_pack_length;
	get_key_length(next_length,keypos);
	get_key_pack_length(prev_length,prev_pack_length,old_key);
	if (next_length > prev_length)
	{
	  /* We have to copy data from the current key to the next key */
	  bmove_upp((char*) keypos,(char*) (lastkey+next_length),
		    (next_length-prev_length));
	  keypos-=(next_length-prev_length)+prev_pack_length;
	  store_key_length(keypos,prev_length);
	  s_length=(int) (keypos-start);
	}
      }
      else
      {
	/* Check if a variable length first key part */
	if ((keyinfo->seg->flag & HA_PACK_KEY) && *keypos & 128)
	{
	  /* Next key is packed against the current one */
	  uint next_length,prev_length,prev_pack_length,lastkey_length,
	    rest_length;
	  if (keyinfo->seg[0].length >= 127)
	  {
	    if (!(prev_length=mi_uint2korr(start) & 32767))
	      goto end;
	    next_length=mi_uint2korr(keypos) & 32767;
	    keypos+=2;
	    prev_pack_length=2;
	  }
	  else
	  {
	    if (!(prev_length= *start & 127))
	      goto end;				/* Same key as previous*/
	    next_length= *keypos & 127;
	    keypos++;
	    prev_pack_length=1;
	  }
	  if (!(*start & 128))
	    prev_length=0;			/* prev key not packed */
	  if (keyinfo->seg[0].flag & HA_NULL_PART)
	    lastkey++;				/* Skipp null marker */
	  get_key_length(lastkey_length,lastkey);
	  if (!next_length)			/* Same key after */
	  {
	    next_length=lastkey_length;
	    rest_length=0;
	  }
	  else
	    get_key_length(rest_length,keypos);

	  if (next_length > prev_length)
	  {		/* Key after is based on deleted key */
	    uint pack_length,tmp;
	    bmove_upp((char*) keypos,(char*) (lastkey+next_length),
		      tmp=(next_length-prev_length));
	    rest_length+=tmp;
	    pack_length= prev_length ? get_pack_length(rest_length): 0;
	    keypos-=tmp+pack_length+prev_pack_length;
	    s_length=(int) (keypos-start);
	    if (prev_length)			/* Pack against prev key */
	    {
	      *keypos++= start[0];
	      if (prev_pack_length == 2)
		*keypos++= start[1];
	      store_key_length(keypos,rest_length);
	    }
	    else
	    {
	      /* Next key is not packed anymore */
	      if (keyinfo->seg[0].flag & HA_NULL_PART)
	      {
		rest_length++;			/* Mark not null */
	      }
	      if (prev_pack_length == 2)
	      {
		mi_int2store(keypos,rest_length);
	      }
	      else
		*keypos= rest_length;
	    }
	  }
	}
      }
    }
  }
  end:
  bmove((byte*) start,(byte*) start+s_length,
	(uint) (page_end-start-s_length));
  DBUG_RETURN((uint) s_length);
} /* remove_key */