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Overview
Comment:More improvements to sqlite3BtreeMovetoUnpacked() performance.
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Timelines: family | ancestors | descendants | both | btree-optimization
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SHA1: 88680698231b7141401f7166e3aff8dbc6008030
User & Date: drh 2013-11-25 14:10:15.692
Context
2013-11-25
15:01
More optimizations to sqlite3BtreeMovetoUnpacked(). But there are failures in TH3. Committing this intermediate state to facilitate bisecting. (check-in: f80497be44 user: drh tags: btree-optimization)
14:10
More improvements to sqlite3BtreeMovetoUnpacked() performance. (check-in: 8868069823 user: drh tags: btree-optimization)
02:38
Performance improvements in sqlite3BtreeMovetoUnpacked(). (check-in: d0fb7acea7 user: drh tags: btree-optimization)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/btree.c.
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    ** 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.  */
    assert( pPage->nCell>0 );
    assert( pPage->intKey==(pIdxKey==0) );
    lwr = 0;
    upr = pPage->nCell-1;
    if( biasRight ){
      pCur->aiIdx[pCur->iPage] = (u16)(idx = upr);
    idx = biasRight ? upr : (upr+lwr)/2;
    pCur->aiIdx[pCur->iPage] = (u16)idx;
    }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;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          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);
        if( lwr>upr ){
          c = nCellKey<intKey ? -1 : +1;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          break;
        }
        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
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          btreeParseCellPtr(pPage, pCellBody, &pCur->info);
          nCell = (int)pCur->info.nKey;
          pCellKey = sqlite3Malloc( nCell );
          if( pCellKey==0 ){
            rc = SQLITE_NOMEM;
            goto moveto_finish;
          }
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
          if( rc ){
            sqlite3_free(pCellKey);
            goto moveto_finish;
          }
          c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
          sqlite3_free(pCellKey);
        }
        if( c==0 ){
          *pRes = 0;
          rc = SQLITE_OK;
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          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);
        if( lwr>upr ){
          pCur->aiIdx[pCur->iPage] = (u16)idx;
          break;
        }
        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;
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