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Overview
Comment:Optimization to sqltie3BtreeParseCellPtr. 0.3% performance increase. (CVS 5432)
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SHA1: 77e099ad7de84fe07dfeb4c045c769653dd13b93
User & Date: drh 2008-07-18 00:57:33.000
Context
2008-07-18
02:44
Omit the check for cell-pointer consistency in sqlite3BtreeInitPage() for a 2.5% performance gain. (CVS 5433) (check-in: b88087e69d user: drh tags: trunk)
00:57
Optimization to sqltie3BtreeParseCellPtr. 0.3% performance increase. (CVS 5432) (check-in: 77e099ad7d user: drh tags: trunk)
2008-07-17
18:39
Simplify the b-tree logic by taking advantage of the fact that all b-trees are either intkey+leafdata or zerodata. (CVS 5431) (check-in: 29d3bfd7c9 user: drh tags: trunk)
Changes
Unified Diff Show Whitespace Changes Patch
Changes to src/btree.c. 
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/*
** 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 1.484 2008/07/17 18:39:58 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"













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/*
** 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 1.485 2008/07/18 00:57:33 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"
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  assert( sqlite3_mutex_held(pPage->pBt->mutex) );

  pInfo->pCell = pCell;
  assert( pPage->leaf==0 || pPage->leaf==1 );
  n = pPage->childPtrSize;
  assert( n==4-4*pPage->leaf );

  if( pPage->hasData ){
    n += getVarint32(&pCell[n], nPayload);
  }else{
    nPayload = 0;
  }

  pInfo->nData = nPayload;
  if( pPage->intKey ){
    n += getVarint(&pCell[n], (u64 *)&pInfo->nKey);
  }else{
    u32 x;

    n += getVarint32(&pCell[n], x);
    pInfo->nKey = x;
    nPayload += x;
  }
  pInfo->nPayload = nPayload;
  pInfo->nHeader = n;
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */
    int nSize;          /* Total size of cell content in bytes */

    pInfo->nLocal = nPayload;
    pInfo->iOverflow = 0;
    nSize = nPayload + n;
    if( nSize<4 ){
      nSize = 4;        /* Minimum cell size is 4 */
    }
    pInfo->nSize = nSize;
  }else{
    /* If the payload will not fit completely on the local page, we have
    ** to decide how much to store locally and how much to spill onto
    ** overflow pages.  The strategy is to minimize the amount of unused








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  assert( sqlite3_mutex_held(pPage->pBt->mutex) );

  pInfo->pCell = pCell;
  assert( pPage->leaf==0 || pPage->leaf==1 );
  n = pPage->childPtrSize;
  assert( n==4-4*pPage->leaf );
  if( pPage->intKey ){
  if( pPage->hasData ){
    n += getVarint32(&pCell[n], nPayload);
  }else{
    nPayload = 0;
  }
    n += getVarint(&pCell[n], (u64*)&pInfo->nKey);
  pInfo->nData = nPayload;


  }else{

    pInfo->nData = 0;
    n += getVarint32(&pCell[n], nPayload);
    pInfo->nKey = nPayload;

  }
  pInfo->nPayload = nPayload;
  pInfo->nHeader = n;
  if( likely(nPayload<=pPage->maxLocal) ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
    */
    int nSize;          /* Total size of cell content in bytes */
    nSize = nPayload + n;
    pInfo->nLocal = nPayload;
    pInfo->iOverflow = 0;
    if( (nSize & ~3)==0 ){

      nSize = 4;        /* Minimum cell size is 4 */
    }
    pInfo->nSize = nSize;
  }else{
    /* If the payload will not fit completely on the local page, we have
    ** to decide how much to store locally and how much to spill onto
    ** overflow pages.  The strategy is to minimize the amount of unused
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