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Overview
Comment:A better implementation of the moveto-neighbor optimization that checks for nearby rows on adjacent pages.
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Timelines: family | ancestors | descendants | both | btree-moveto-neighbor
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SHA1: 2c4ecb85a475b9063aa8a3bb517ac181a7ded649
User & Date: drh 2017-01-21 21:47:54
Context
2017-01-23
16:56
Optimization: Try to avoid unnecessary btree searching when repositioning a cursor to the next row. check-in: ee793d30 user: drh tags: trunk
2017-01-21
21:47
A better implementation of the moveto-neighbor optimization that checks for nearby rows on adjacent pages. Closed-Leaf check-in: 2c4ecb85 user: drh tags: btree-moveto-neighbor
16:54
B-tree optimization: When seeking on a rowid table that has already been positioned, check to see if the new row happens to be the next row on the same leaf page. That is a reasonably common case, and if it is true it avoids a full binary search. check-in: 8e5cfb20 user: drh tags: btree-moveto-neighbor
Changes
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Changes to src/btree.c.

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      return SQLITE_OK;
    }
    if( pCur->info.nKey<intKey ){
      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
        *pRes = -1;
        return SQLITE_OK;
      }
      if( pCur->aiIdx[pCur->iPage]+1<pCur->apPage[pCur->iPage]->nCell ){
        pCur->aiIdx[pCur->iPage]++;
        pCur->info.nSize = 0;
        pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);





        getCellInfo(pCur);
        if( pCur->info.nKey==intKey ){
          *pRes = 0;
          return SQLITE_OK;

        }
      }
    }
  }

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);







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      return SQLITE_OK;
    }
    if( pCur->info.nKey<intKey ){
      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
        *pRes = -1;
        return SQLITE_OK;
      }
      /* If the requested key is one more than the previous key, then
      ** try to get there using sqlite3BtreeNext() rather than a full
      ** binary search.  This is an optimization only.  The correct answer
      ** is still obtained without this ase, only a little more slowely */
      if( pCur->info.nKey+1==intKey && !pCur->skipNext ){
        *pRes = 0;
        rc = sqlite3BtreeNext(pCur, pRes);
        if( rc ) return rc;
        if( *pRes==0 ){
          getCellInfo(pCur);
          if( pCur->info.nKey==intKey ){

            return SQLITE_OK;
          }
        }
      }
    }
  }

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);