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Overview
Comment:Simplifications to the VdbeCursor object.
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SHA1: 5562cd343d8f69242e06a51a7f1aef7ee7d78eec
User & Date: drh 2013-11-20 02:53:58.741
Context
2013-11-21
01:33
Refactor the OP_Column opcode to make it clearer and easier to maintain. Overall, performance tests show about a 1% speed increase with this change. (check-in: 972881c6d3 user: drh tags: trunk)
2013-11-20
17:25
Refactoring the OP_Column opcode for improved performance and maintainability. (check-in: 7c914e3997 user: drh tags: OP_Column-refactor)
02:53
Simplifications to the VdbeCursor object. (check-in: 5562cd343d user: drh tags: trunk)
00:59
Performance improvement for the OP_MustBeInt opcode in the VDBE. (check-in: 96a65388e7 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/expr.c.
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    return WRC_Abort;
  }

  switch( pExpr->op ){
    /* Consider functions to be constant if all their arguments are constant
    ** and pWalker->u.i==2 */
    case TK_FUNCTION:
      if( pWalker->u.i==2 ) return 0;
      /* Fall through */
    case TK_ID:
    case TK_COLUMN:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
      testcase( pExpr->op==TK_ID );
      testcase( pExpr->op==TK_COLUMN );








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    return WRC_Abort;
  }

  switch( pExpr->op ){
    /* Consider functions to be constant if all their arguments are constant
    ** and pWalker->u.i==2 */
    case TK_FUNCTION:
      if( pWalker->u.i==2 ) return WRC_Continue;
      /* Fall through */
    case TK_ID:
    case TK_COLUMN:
    case TK_AGG_FUNCTION:
    case TK_AGG_COLUMN:
      testcase( pExpr->op==TK_ID );
      testcase( pExpr->op==TK_COLUMN );
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Changes to src/vdbe.c.
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  res = 1;
  if( isSorter(pC) ){
    rc = sqlite3VdbeSorterRewind(db, pC, &res);
  }else{
    pCrsr = pC->pCursor;
    assert( pCrsr );
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->atFirst = res==0 ?1:0;
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
    pC->rowidIsValid = 0;
  }
  pC->nullRow = (u8)res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){








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  res = 1;
  if( isSorter(pC) ){
    rc = sqlite3VdbeSorterRewind(db, pC, &res);
  }else{
    pCrsr = pC->pCursor;
    assert( pCrsr );
    rc = sqlite3BtreeFirst(pCrsr, &res);

    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
    pC->rowidIsValid = 0;
  }
  pC->nullRow = (u8)res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){
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Changes to src/vdbeInt.h.
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** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct VdbeCursor {
  BtCursor *pCursor;    /* The cursor structure of the backend */
  Btree *pBt;           /* Separate file holding temporary table */
  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
  int pseudoTableReg;   /* Register holding pseudotable content. */
  int nField;           /* Number of fields in the header */
  Bool zeroed;          /* True if zeroed out and ready for reuse */
  Bool rowidIsValid;    /* True if lastRowid is valid */
  Bool atFirst;         /* True if pointing to first entry */
  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
  Bool nullRow;         /* True if pointing to a row with no data */
  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */
  Bool isTable;         /* True if a table requiring integer keys */
  Bool isIndex;         /* True if an index containing keys only - no data */
  Bool isOrdered;       /* True if the underlying table is BTREE_UNORDERED */
  Bool isSorter;        /* True if a new-style sorter */
  Bool multiPseudo;     /* Multi-register pseudo-cursor */
  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Last rowid from a Next or NextIdx operation */
  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */

  /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists */
  int seekResult;

  /* Cached information about the header for the data record that the
  ** cursor is currently pointing to.  Only valid if cacheStatus matches








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** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct VdbeCursor {
  BtCursor *pCursor;    /* The cursor structure of the backend */
  Btree *pBt;           /* Separate file holding temporary table */
  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */

  int pseudoTableReg;   /* Register holding pseudotable content. */
  i16 nField;           /* Number of fields in the header */
  i8 iDb;               /* Index of cursor database in db->aDb[] (or -1) */
  Bool rowidIsValid;    /* True if lastRowid is valid */

  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */
  Bool nullRow;         /* True if pointing to a row with no data */
  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */
  Bool isTable;         /* True if a table requiring integer keys */
  Bool isIndex;         /* True if an index containing keys only - no data */
  Bool isOrdered;       /* True if the underlying table is BTREE_UNORDERED */
  Bool isSorter;        /* True if a new-style sorter */
  Bool multiPseudo;     /* Multi-register pseudo-cursor */
  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Rowid being deleted by OP_Delete */
  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */

  /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists */
  int seekResult;

  /* Cached information about the header for the data record that the
  ** cursor is currently pointing to.  Only valid if cacheStatus matches
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