SQLite

Check-in [d99bde9ca6]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Unwind some complex conditions in sqlite3BtreeDelete() into separate "if" statements. (CVS 6879)
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: d99bde9ca61eeccfe6363ff0882fd4bcdb9a34dc
User & Date: drh 2009-07-11 13:13:12.000
Context
2009-07-11
17:04
Bug fix in the computation of the number of pages to autovacuum when nReserve is greater than zero. (CVS 6880) (check-in: 618a83d65f user: drh tags: trunk)
13:13
Unwind some complex conditions in sqlite3BtreeDelete() into separate "if" statements. (CVS 6879) (check-in: d99bde9ca6 user: drh tags: trunk)
11:45
Remove another unreachable branch from btree.c. (CVS 6878) (check-in: b0853100a9 user: danielk1977 tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c. 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.677 2009/07/11 11:45:23 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"













|








1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.678 2009/07/11 13:13:12 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"
︙︙
6547
6548
6549
6550
6551
6552
6553
6554

6555

6556

6557

6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581

6582

6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593

      return rc;
    }
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 
  ** entry and finally remove the cell itself from within the page.  */

  if( SQLITE_OK!=(rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur))

   || SQLITE_OK!=(rc = sqlite3PagerWrite(pPage->pDbPage))

   || SQLITE_OK!=(rc = clearCell(pPage, pCell))

   || SQLITE_OK!=(rc = dropCell(pPage, iCellIdx, cellSizePtr(pPage, pCell)))
  ){
    return rc;
  }

  /* If the cell deleted was not located on a leaf page, then the cursor
  ** is currently pointing to the largest entry in the sub-tree headed
  ** by the child-page of the cell that was just deleted from an internal
  ** node. The cell from the leaf node needs to be moved to the internal
  ** node to replace the deleted cell.  */
  if( !pPage->leaf ){
    MemPage *pLeaf = pCur->apPage[pCur->iPage];
    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt)>=nCell );

    allocateTempSpace(pBt);
    pTmp = pBt->pTmpSpace;

    if( SQLITE_OK!=(rc = sqlite3PagerWrite(pLeaf->pDbPage)) 

     || SQLITE_OK!=(rc = insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n))

     || SQLITE_OK!=(rc = dropCell(pLeaf, pLeaf->nCell-1, nCell))
    ){
      return rc;
    }
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
  ** then the cursor still points to that page. In this case the first
  ** call to balance() repairs the tree, and the if(...) condition is
  ** never true.
  **








|
>
|
>
|
>
|
>
|
<
|
<



















|
>
|
>
|
<
|
<








6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562

6563

6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587

6588

6589
6590
6591
6592
6593
6594
6595

      return rc;
    }
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 
  ** entry and finally remove the cell itself from within the page.  
  */
  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
  if( rc ) return rc;
  rc = sqlite3PagerWrite(pPage->pDbPage);
  if( rc ) return rc;
  rc = clearCell(pPage, pCell);
  if( rc ) return rc;
  rc = dropCell(pPage, iCellIdx, cellSizePtr(pPage, pCell));

  if( rc ) return rc;


  /* If the cell deleted was not located on a leaf page, then the cursor
  ** is currently pointing to the largest entry in the sub-tree headed
  ** by the child-page of the cell that was just deleted from an internal
  ** node. The cell from the leaf node needs to be moved to the internal
  ** node to replace the deleted cell.  */
  if( !pPage->leaf ){
    MemPage *pLeaf = pCur->apPage[pCur->iPage];
    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt)>=nCell );

    allocateTempSpace(pBt);
    pTmp = pBt->pTmpSpace;

    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    if( rc ) return rc;
    rc = insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n);
    if( rc ) return rc;
    rc = dropCell(pLeaf, pLeaf->nCell-1, nCell);

    if( rc ) return rc;

  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
  ** then the cursor still points to that page. In this case the first
  ** call to balance() repairs the tree, and the if(...) condition is
  ** never true.
  **
︙︙