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Overview
Comment:Small performance optimization in sqlite3WhereExprUsage().
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SHA3-256: 38edc6770e54e456500e77389d42fdf39e9a7ed258a4e1fed3c6dd8fdf4dfcb7
User & Date: drh 2017-07-10 15:26:09.382
Context
2017-07-10
16:38
Additional debugging Noop-comment in the constraint generator when wheretrace is enabled. (Closed-Leaf check-in: 0ca7474f05 user: drh tags: defer-where-subqueries)
15:26
Small performance optimization in sqlite3WhereExprUsage(). (check-in: 38edc6770e user: drh tags: defer-where-subqueries)
15:17
Fix another problem on this branch. (check-in: a4fc98113a user: dan tags: defer-where-subqueries)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/whereexpr.c.
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  Bitmask mask;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
    return sqlite3WhereGetMask(pMaskSet, p->iTable);
  }
  mask = (p->op==TK_IF_NULL_ROW) ? sqlite3WhereGetMask(pMaskSet, p->iTable) : 0;
  assert( !ExprHasProperty(p, EP_TokenOnly) );
  if( p->pRight ) mask |= sqlite3WhereExprUsage(pMaskSet, p->pRight);
  if( p->pLeft ) mask |= sqlite3WhereExprUsage(pMaskSet, p->pLeft);
  if( ExprHasProperty(p, EP_xIsSelect) ){
  if( p->pLeft ) mask |= sqlite3WhereExprUsage(pMaskSet, p->pLeft);
  if( p->pRight ){
    mask |= sqlite3WhereExprUsage(pMaskSet, p->pRight);
    assert( p->x.pList==0 );
  }else if( ExprHasProperty(p, EP_xIsSelect) ){
    if( ExprHasProperty(p, EP_VarSelect) ) pMaskSet->bVarSelect = 1;
    mask |= exprSelectUsage(pMaskSet, p->x.pSelect);
  }else if( p->x.pList ){
    mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList);
  }
  return mask;
}
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