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Overview
Comment:Performance improvements in sqlite3BtreeMovetoUnpacked().
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Timelines: family | ancestors | descendants | both | btree-optimization
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SHA1:d0fb7acea7cbfe6f2d84782a28bb51675a06576f
User & Date: drh 2013-11-25 02:38:55
Context
2013-11-25
14:10
More improvements to sqlite3BtreeMovetoUnpacked() performance. check-in: 88680698 user: drh tags: btree-optimization
02:38
Performance improvements in sqlite3BtreeMovetoUnpacked(). check-in: d0fb7ace user: drh tags: btree-optimization
2013-11-24
01:14
Add the --scratch parameter to speedtest1. Improved error messages when misconfiguring memory parameters in speedtest1. check-in: 8f3c767a user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/btree.c.

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  if( pCur->eState==CURSOR_INVALID ){
    *pRes = -1;
    assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
    return SQLITE_OK;
  }
  assert( pCur->apPage[0]->intKey || pIdxKey );
  for(;;){
    int lwr, upr, idx;
    Pgno chldPg;
    MemPage *pPage = pCur->apPage[pCur->iPage];
    int c;

    /* pPage->nCell must be greater than zero. If this is the root-page
    ** the cursor would have been INVALID above and this for(;;) loop
    ** not run. If this is not the root-page, then the moveToChild() routine
    ** would have already detected db corruption. Similarly, pPage must
    ** be the right kind (index or table) of b-tree page. Otherwise
    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
................................................................................
    lwr = 0;
    upr = pPage->nCell-1;
    if( biasRight ){
      pCur->aiIdx[pCur->iPage] = (u16)(idx = upr);
    }else{
      pCur->aiIdx[pCur->iPage] = (u16)(idx = (upr+lwr)/2);
    }
    for(;;){
      u8 *pCell;                          /* Pointer to current cell in pPage */

      assert( idx==pCur->aiIdx[pCur->iPage] );
      pCur->info.nSize = 0;
      pCell = findCell(pPage, idx) + pPage->childPtrSize;
      if( pPage->intKey ){


        i64 nCellKey;

        if( pPage->hasData ){
          u32 dummy;
          pCell += getVarint32(pCell, dummy);
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey==intKey ){






          c = 0;



        }else if( nCellKey<intKey ){
          c = -1;

        }else{
          assert( nCellKey>intKey );
          c = +1;

        }
        pCur->validNKey = 1;
        pCur->info.nKey = nCellKey;


      }else{





        /* The maximum supported page-size is 65536 bytes. This means that
        ** the maximum number of record bytes stored on an index B-Tree
        ** page is less than 16384 bytes and may be stored as a 2-byte
        ** varint. This information is used to attempt to avoid parsing 
        ** the entire cell by checking for the cases where the record is 
        ** stored entirely within the b-tree page by inspecting the first 
        ** 2 bytes of the cell.
        */
        int nCell = pCell[0];
        if( nCell<=pPage->max1bytePayload
         /* && (pCell+nCell)<pPage->aDataEnd */
        ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
................................................................................
          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
          sqlite3_free(pCellKey);
        }
      }
      if( c==0 ){
        if( pPage->intKey && !pPage->leaf ){
          lwr = idx;
          break;
        }else{
          *pRes = 0;
          rc = SQLITE_OK;
          goto moveto_finish;
        }
      }
      if( c<0 ){
        lwr = idx+1;
      }else{
        upr = idx-1;
      }
      if( lwr>upr ){
        break;
      }
      pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);

    }
    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
    assert( pPage->isInit );
    if( pPage->leaf ){
      chldPg = 0;



    }else if( lwr>=pPage->nCell ){
      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    }else{
      chldPg = get4byte(findCell(pPage, lwr));
    }
    if( chldPg==0 ){
      assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
      *pRes = c;
      rc = SQLITE_OK;
      goto moveto_finish;
    }
    pCur->aiIdx[pCur->iPage] = (u16)lwr;
    pCur->info.nSize = 0;
    pCur->validNKey = 0;
    rc = moveToChild(pCur, chldPg);
    if( rc ) goto moveto_finish;
  }
moveto_finish:
  return rc;
}


/*







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  if( pCur->eState==CURSOR_INVALID ){
    *pRes = -1;
    assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
    return SQLITE_OK;
  }
  assert( pCur->apPage[0]->intKey || pIdxKey );
  for(;;){
    int lwr, upr, idx, c;
    Pgno chldPg;
    MemPage *pPage = pCur->apPage[pCur->iPage];
    u8 *pCell;                          /* Pointer to current cell in pPage */

    /* pPage->nCell must be greater than zero. If this is the root-page
    ** the cursor would have been INVALID above and this for(;;) loop
    ** not run. If this is not the root-page, then the moveToChild() routine
    ** would have already detected db corruption. Similarly, pPage must
    ** be the right kind (index or table) of b-tree page. Otherwise
    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
................................................................................
    lwr = 0;
    upr = pPage->nCell-1;
    if( biasRight ){
      pCur->aiIdx[pCur->iPage] = (u16)(idx = upr);
    }else{
      pCur->aiIdx[pCur->iPage] = (u16)(idx = (upr+lwr)/2);
    }




    pCur->info.nSize = 0;

    if( pPage->intKey ){
      assert( idx==pCur->aiIdx[pCur->iPage] );
      for(;;){
        i64 nCellKey;
        pCell = findCell(pPage, idx) + pPage->childPtrSize;
        if( pPage->hasData ){
          u32 dummy;
          pCell += getVarint32(pCell, dummy);
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey==intKey ){
          pCur->validNKey = 1;
          pCur->info.nKey = nCellKey;
          if( !pPage->leaf ){
            lwr = idx;
            break;
          }else{
            *pRes = 0;
            rc = SQLITE_OK;
            goto moveto_finish;
          }
        }else if( nCellKey<intKey ){
          c = -1;
          lwr = idx+1;
        }else{
          assert( nCellKey>intKey );
          c = +1;
          upr = idx-1;
        }

        if( lwr>upr ) break;
        pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
      }
    }else{
      for(;;){
        int nCell;
        assert( idx==pCur->aiIdx[pCur->iPage] );
        pCell = findCell(pPage, idx) + pPage->childPtrSize;

        /* The maximum supported page-size is 65536 bytes. This means that
        ** the maximum number of record bytes stored on an index B-Tree
        ** page is less than 16384 bytes and may be stored as a 2-byte
        ** varint. This information is used to attempt to avoid parsing 
        ** the entire cell by checking for the cases where the record is 
        ** stored entirely within the b-tree page by inspecting the first 
        ** 2 bytes of the cell.
        */
        nCell = pCell[0];
        if( nCell<=pPage->max1bytePayload
         /* && (pCell+nCell)<pPage->aDataEnd */
        ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
................................................................................
          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
          sqlite3_free(pCellKey);
        }

        if( c==0 ){




          *pRes = 0;
          rc = SQLITE_OK;
          goto moveto_finish;
        }

        if( c<0 ){
          lwr = idx+1;
        }else{
          upr = idx-1;
        }
        if( lwr>upr ) break;


        pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
      }
    }
    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
    assert( pPage->isInit );
    if( pPage->leaf ){
      assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
      *pRes = c;
      rc = SQLITE_OK;
      goto moveto_finish;
    }else if( lwr>=pPage->nCell ){
      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    }else{
      chldPg = get4byte(findCell(pPage, lwr));
    }






    pCur->aiIdx[pCur->iPage] = (u16)lwr;
    pCur->info.nSize = 0;
    pCur->validNKey = 0;
    rc = moveToChild(pCur, chldPg);
    if( rc ) break;
  }
moveto_finish:
  return rc;
}


/*