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Overview
Comment:Fix the assert()s in the byte-code engine that prove that cursors are unidirectional.
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Timelines: family | ancestors | descendants | both | multikey-opt-idea
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SHA3-256: 4b0b4e14039469b656662312a5f80f086ede293e9ad04c7bc99a202b683a1e55
User & Date: drh 2018-06-07 18:01:21.263
Context
2018-06-07
18:13
The IN-early-out optimization: When doing a look-up on a multi-column index and an IN operator is used on a column other than the left-most column, then if no rows match against the first IN value, check to make sure there exist rows that match the columns to the right before continuing with the next IN value. (check-in: 09fffbdf9f user: drh tags: trunk)
18:01
Fix the assert()s in the byte-code engine that prove that cursors are unidirectional. (Closed-Leaf check-in: 4b0b4e1403 user: drh tags: multikey-opt-idea)
17:32
Remove the NextIfOpen and PrevIfOpen opcodes which are no longer needed when the IN-early-out optimization is working. (check-in: 439c816227 user: drh tags: multikey-opt-idea)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/vdbe.c.
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case OP_NotExists:          /* jump, in3 */
  pIn3 = &aMem[pOp->p3];
  assert( pIn3->flags & MEM_Int );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = 0;
#endif
  assert( pC->isTable );
  assert( pC->eCurType==CURTYPE_BTREE );
  pCrsr = pC->uc.pCursor;
  assert( pCrsr!=0 );
  res = 0;
  iKey = pIn3->u.i;








|








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case OP_NotExists:          /* jump, in3 */
  pIn3 = &aMem[pOp->p3];
  assert( pIn3->flags & MEM_Int );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = OP_SeekRowid;
#endif
  assert( pC->isTable );
  assert( pC->eCurType==CURTYPE_BTREE );
  pCrsr = pC->uc.pCursor;
  assert( pCrsr!=0 );
  res = 0;
  iKey = pIn3->u.i;
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  assert( pC!=0 );
  pC->nullRow = 1;
  pC->cacheStatus = CACHE_STALE;
  if( pC->eCurType==CURTYPE_BTREE ){
    assert( pC->uc.pCursor!=0 );
    sqlite3BtreeClearCursor(pC->uc.pCursor);
  }



  break;
}

/* Opcode: SeekEnd P1 * * * *
**
** Position cursor P1 at the end of the btree for the purpose of
** appending a new entry onto the btree.








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  assert( pC!=0 );
  pC->nullRow = 1;
  pC->cacheStatus = CACHE_STALE;
  if( pC->eCurType==CURTYPE_BTREE ){
    assert( pC->uc.pCursor!=0 );
    sqlite3BtreeClearCursor(pC->uc.pCursor);
  }
#ifdef SQLITE_DEBUG
  if( pC->seekOp==0 ) pC->seekOp = OP_NullRow;
#endif
  break;
}

/* Opcode: SeekEnd P1 * * * *
**
** Position cursor P1 at the end of the btree for the purpose of
** appending a new entry onto the btree.
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  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );

#if 0
  /* The Next opcode is only used after SeekGT, SeekGE, and Rewind.
  ** The Prev opcode is only used after SeekLT, SeekLE, and Last. */
  assert( pOp->opcode!=OP_Next
       || pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
       || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found);

  assert( pOp->opcode!=OP_Prev
       || pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE

       || pC->seekOp==OP_Last );
#endif

  rc = pOp->p4.xAdvance(pC->uc.pCursor, pOp->p3);
next_tail:
  pC->cacheStatus = CACHE_STALE;
  VdbeBranchTaken(rc==SQLITE_OK,2);
  if( rc==SQLITE_OK ){
    pC->nullRow = 0;








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  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );


  /* The Next opcode is only used after SeekGT, SeekGE, Rewind, and Found.
  ** The Prev opcode is only used after SeekLT, SeekLE, and Last. */
  assert( pOp->opcode!=OP_Next
       || pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
       || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found 
       || pC->seekOp==OP_NullRow);
  assert( pOp->opcode!=OP_Prev
       || pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
       || pC->seekOp==OP_Last 
       || pC->seekOp==OP_NullRow);


  rc = pOp->p4.xAdvance(pC->uc.pCursor, pOp->p3);
next_tail:
  pC->cacheStatus = CACHE_STALE;
  VdbeBranchTaken(rc==SQLITE_OK,2);
  if( rc==SQLITE_OK ){
    pC->nullRow = 0;
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